A boy earned $435, $230, and $562 for 3 consecutive months. How much did he earn in the fourth month so that he gets an average earning of $500 in these 4 months?

1) First, we need to find the total amount of money he needs so that the average of the 4 months would be 500. We can do this by multiplying 500 and 4 (essentially, we are working backward when trying to find the average) [tex]500*4=2000[/tex] So, we know that the boy needs $2000 total by the end of the fourth month to make the 4-month average $500.

2) Now, we know how much the boy made for the first 3 consecutive months, so add those numbers up. [tex]435+230+562=1227[/tex] So within the first 3 months, the boy made $1227.

3) Finally, we know how much money the boy needs by the end of the fourth month and how much he made by the third, so to figure out how much he earned in the fourth month, we can simply subtract $1227 from $2000. [tex]2000-1227=773[/tex]