Three of the following test scores are Cyprian's and the other three are Margaret's: 85, 87, 92, 93, 94, 98. Cyprian's mean score is 90. What is Margaret's mean score?
I need to find the average of Margaret's three test scores, but I don't know which ones they are. I do know that Cyprian's mean score is 90, which means that the sum of his three scores is 3 times 90, or 270. Therefore, the sum of Margaret's three scores must be 549 - 270, which is 279. To find Margaret's mean score, I need to divide the sum of her scores by 3. So, Margaret's mean score is 279 divided by 3, which is 93. 