hey these smart monkeys and welcome to my channel this is a channel where I turn struggling math students into maths Masters I post videos every Tuesday and Thursday so be sure to subscribe and turn on the Bell to get notified when I post any videos okay so in this video we're gonna look at distance speed and time it's a fairly simple concept but the idea is to make this even easier so that when you see it you have the confidence to take on the question and the focus is also really on looking at time and just all sort of the the intricacies that comes with time when you're actually working with distance and speed all right so yeah let's do this thank you [Music] okay so in this lesson like I mentioned we're going to look at distance speed and time okay so I'm really gonna focus on the areas that sort of are not as clear-cut or not as easy okay so we're gonna first start I like to start at the Bare Basics so that everybody at least knows what we are doing and then I will go to sort of the more in-depth type of questions okay so let's just first make sure we understand the definition so if you look at Point a and point B then we'll know that distance is basically asking or referring to how far is a from B and then the speed would be would refer to how fast am I moving from point A to point B or from B to point a and then time is how long is it taking me to travel from point A to point B so these are the sort of the definitions that you need to be very clear on before you take on and and go into the sort of intricacies of the section okay so the nice wave or the way I explain this to my students is I say the triangle is fairly simple way to really understand this so if you think of a triangle and whenever there's a distance speed and time question I always tell my students through this triangle okay and um so the D will always be on top and the SD at the bottom and essentially what this means is that if this if whatever is being asked right you always put sort of cover in this triangle so if I'm being asked distance I will cover the D and then I'm left with SNT that are next to each other so if they are next to each other then that means our calculation is multiply okay if the one is on top of the other then that means it's divide so in this case distance if I cover the D would equal speed multiplied by time also if we now being asked for time then we will cover the T and then the calculation will always be the distance over speed okay and then the last one will be the average speed we'll then be covering is and then we'll see distance over time okay so these formulas are generally given to you but what I realized they do or when they try and sort of trick you and give you sort of more challenging questions this way they'll maybe give you the first Formula so distance equals average speed multiplied by time and then not ask distance then they give you the distance and they give you the time and you have to know how to then calculate the average speed okay so I always say this triangle will cover you you will know what you need to divide and what you need to multiply by what if you actually understand and memorize this triangle okay so now let's actually look at some questions okay but before we look at some questions I want to just maybe emphasize and I'm gonna if we look at this I want you to just always remember when we're looking at a unit distance obviously will always be length so it will be meters kilometers um centimeters Etc and then the time will always be hours or minutes or seconds but what speed is is speeds unit is always dependent on what the distance and the times unit is so if my distance is kilometers and my time is hours then my speed would refer to kilometers per hour okay if my distance was meters and my time was seconds then it would be meters per second so s is always s's units is always a combination of the distance and the times unit okay now that we got that out of the way I'm gonna do one example of each okay where you need to calculate each and then we're going to sort of look at certain um sections where sort of things get a little bit challenging and I can just show you how you would actually approach that that specific aspect of the questions okay so cheaper travels at 130 kilometers average speed of 120 kilometers per hour to a work conference calculate how long it took him obviously to travel that distance and then give your answer in hours and minutes okay so the calculation is pretty easy it's where things get tricky is the hours and minutes so let me show you how you can approach this so firstly we look at the triangle flatten the triangle and we look at the triangle we use the triangle and we see what is given so it travels 130 kilometers so that's our distance right he they give us the average speed right so essentially if I look at my triangle right according to this it would mean that we have distances kilometers and the speed they're giving us is kilometers per hour so we know if we had to anyway do any of these calculations to calculate time that our answer would then be in hours because the speed is always a combination of distance and time so because I'm asking they're asking me for time I cover the T and then that would mean that it would be D divided by S right so that would mean I'll take the 130 and divide it by the 120. okay and that will give me 1.08333 hours okay so usually most students get to this point it's fine but now how do you take this and convert it to hours and minutes now the mistake that most people make and I'm pleased asking you not to make this mistake because you don't have to lose these marks but a lot of kids then will say okay this is one hour and 0.8333 minutes which is incorrect okay how are you going to do this is the number in front of the decimal will always be your hours so that will remain the same okay but what you need to do is you're going to take the 0.0833 what's left and multiply that by 60 because we get we have 60 minutes in an hour right so if we multiply it by 60 then we get an answer of five and then that is then gives us our minutes so in essence typo then took one hour and five minutes to get from um to travel to his work conference okay so what did I do here I took the one the one is in front of the decimal so whatever's in front of the decimal Remains the hours and whatever is after the decimal you then take that value by itself without the hours and multiplied by 60 to find your minutes okay and that's how I got one hour and five minutes so you see in essence the first part is the easy calculation but it's making sure that you know how to give the answer that's important in the second example now we're going to look at um the scenario so cheaper travels at 1.2 million meters to visit his mom anxiety travels for 13 hours and 20 minutes calculate his average speed so now we break down what do we have okay we've got distance in the question and we've got the time okay so based on our triangle that means if we have distance in time they are asking us to calculate the speed and how do we calculate the speed it's the distance over the time now when we're calculating the average speed you will remember I mentioned that um the units should be the same so if I want to calculate the average speed in the unit they're asking which is kilometers per hour then that means my distance needs to be in kilometers and my time needs to be in hours so that's what we're going to do we're going to convert the distance into kilometers okay so it's divided by a thousand and if you're not sure why I divide by a thousand or how to do this conversion I have a video out on measurements that makes this whole process very easy um it's called converge it's got a video called conversions and I'll link it in the description below so yeah have a look at that but I've now converted the meters to kilometers because they want the speed in kilometers per hour right then I go and I have to convert my 13 hours and 20 minutes into hours so the 13 is already in hours so it's in essence I just need to convert the 20 minutes to hours so how do I do that I say 20 and I divided by 60 now right to give me 0.333 so when I'm going from minutes to hours I divide by 60 and when I'm going from hours to minutes like in the previous example I'm multiply by 60 okay excuse me all right so now if I look you'll see that my hours is then 13 which is the hours in the question and then the decimals I'll just apply from when I converted the minutes so that all of that is in the total hours so in order to calculate the speed I then say 1200 which is now kilometers and I divided by the 13 13.333333 and I get an answer of an average speed of 90 kilometers per hour okay so that is how you would then calculate the speed um remember the speed is always the units it's always a combination of the units of the distance and the time okay um yeah right so let's move to one last example so chippo and Tipo is very busy as you can tell people's traveling very much so tippo Works 31.5 kilometers from home okay and stop and start work at half past nine if he travels at a speed of 75 kilometers per hour and gets to work at exactly 9 30. show whether or not he left home at nine okay so if you look at this question right again we ask ourselves what is given okay so he works 31.5 kilometers from home so that's our distance right then he travels at a speed of 75 kilometers per hour so now they want to know um if he got to work at exactly half past nine did he leave at exactly nine o'clock so we need to calculate the time right so again we've got kilometers and we've got speed and we need to calculate the time so how do we do this we know that it's distance divided by speed so the distance is 31.5 divided by the speed is 75. the speed which is 75 and it gives you 0.42 hours now again that's that's 0.42 is not 42 minutes this whole value is in hours so if I want to calculate how many or if I want to convert this hours into minutes I'm then going to say 0.42 and multiply it by 60 just like we did in example one to give us 25.2 minutes so essentially he traveled for only 25.2 minutes right so did he leave at nine o'clock or did he leave a little bit after nine so if you look from 9 to 9 30 is a 30 minutes but he only traveled for 25.2 minutes so what does that mean that means that he left just a little bit after nine o'clock okay so a way to show this calculation is you'll say if he left home at 9 30 um sorry if you got to work at 9 30 and you subtract the 25.2 minutes then that means he gets her he left at about nine o'clock and 0.48 minutes okay so that's just doing the subtraction calculation day okay so I'm saying 30 just the minutes the 30 minutes minus the 25.2 minutes which will then give us the 04.8 minutes we surrounded off will then be 9.05 so yield five minutes past nine he didn't leave at exactly nine o'clock okay so this is just one way where they can take a simple Concept in the religious sort of spin the question in such a way that you have to answer it and apply what you've answered in in the way we have in this question okay so let's just give you quickly a recap again we have to know that we use the triangle the distance on top and speed and time next to each other whatever they're asking you cover and then whatever is left you do the operation so if they if they're asking distance you cover the D and what's left is speed in time which means you multiply s and t because they're next to each other if they ask you speed you cover the speed and what's left is distance over time and so um you'll then say distance divided by time okay and that's how you will approach these questions to make sure you know when to add when to divide and when to multiply that being said also you have to remember how to convert um minutes and when something's actually in hours with decimals how to take that and convert it to hours and minutes and then if something's in hours and minutes you have to know how to convert that back into just hours okay and then you have to just make sure that you are always reading the questions properly so that you are actually able to understand what they're asking so you can apply what you've learned in this video to actually answer the questions that they are asking okay yeah best of luck for this section and I hope I made this a little bit easier for you all right so that's the end of the video um I hope that you found it helpful and yeah if you liked it please give it a thumbs up and if you have any questions or if you want me to you know make a video in any specific topic feel free to edit in the comment section below and I'll try my best to make sure that I can make it for you um yeah and thank you so much for watching and I'll see you in the next video