this is a thought question where you don't really have to do any calculation and it revolves around the idea of a relative atomic mass atomic weight so let's just do a little bit of review for that let's say that we have a type of pickup truck called the Rodeo pickup truck the rodeo pickup truck comes in two types the rodeo cloud is kind of a dinky little thing that weighs 5,000 lb and the Rodeo Cowboy which is monstrous and weighs 20,000 lb Now what is the average weight of these two pickup trucks if I said average weight what you'd probably do is you would add the two weights together and divide by two and you get 12,500 lb which is right in between 5,000 for the clown and 20,000 for the cowboy but what if I told you this what if I said that most people didn't like to drive the clown because they thought it made them look like losers so only 20% of the rodeo pickup trucks on the road were the rodeo clown on the other hand 80% of the rodeo pickups on the road were the Rodeo Cowboy because people thought it made them look tough so in that case what is the average weight of all of these pickup trucks right cuz they're only 20% of the clown and 80% of the cowboy then this average doesn't really seem to make sense because it assumes that we have the same amount of both of these but we have much more of the cowboy than of a clown and the cow boy weighs a lot more in this case we have to calculate what's called a relative or a weighted average where we take the weight of each one of these and multiply it by the percentage that we have of it so 5,000 lb for the clown times 20% as a decimal plus 20,000 lb for the cowboy time 80% as a decimal and then when we do that we end up with an average that's not right in the middle we end up with an average that's tilted higher closer to the weight of the cowboy and that makes sense because there are many more Cowboy pickups on the road our average of these weights should be closer to the weight of a cowboy