GMAT Quantitative Reasoning Practice Test 3

This is an average problem, so use the average formula. If the average of 8 numbers is $44.1$ , we can solve for their sum: 8 × 44.1 = 352.8. If four of these numbers total $158.4$ , then by subtracting $158.4$ from $352.8$ , we get the sum of the other
four numbers, $194.4$ . To find the average of these 4 numbers, we divide their sum by their number: $\left(194.4\right)/4=48.6.$