Answer :
(98 + 84 + 90 + x) / 4 = 87
87 * 4 = 348
348 - 98 = 250 - 84 = 166 - 90 = 76
She needs a 76%
Double check with (98 + 84 + 90 + 76) / 4 = 87
87 * 4 = 348
348 - 98 = 250 - 84 = 166 - 90 = 76
She needs a 76%
Double check with (98 + 84 + 90 + 76) / 4 = 87