First, we know that in order to find the average of a group of numbers, we need to add all the values together and divide by the number of values. In this case, we can write a formula for the average in order to solve for the unknown test score that Kia needs to receive: 80=(76+85+82+75+74+x)/6 (x represents the unknown test score). The reason we divide by 6 rather than by 5 is because with the new test score, there will be a total of 6 test scores. First, we can simplify the equation to 80=(392+x)/6. Then, we can cross multiply to get 80*6=392+x or 480=392+x. Lastly, we must subtract 392 from both sides to get x=88 so the answer is choice B.
