Question

johns first three test scores out of 100 are 84,78,82. what did he score on his fourth test if the average for all four tests is 80 out of 100

Answer 1

Explanation:

80 * 4 = 320

84 + 78 + 82 + x = 244

244 + x = 320

x = 320 - 244

x = 76

Answer 2

76

Explanation:

In order for John's average to be 80, the sum of all of his test scores must be 4*80 = 320. We can add 84, 78, and 82 to get 244, and then we subtract 244 from 320 to obtain the answer 76.