(87 + 81 + 85 + 90 + 78 + x) / 6 > = 45 <=== ur inequality
(421 + x) / 6 > = 45
421 + x > = 45 * 6
421 + x > = 270
x > = 270 - 421
x > = -151
u sure this problem is typed in correctly ? Because for her to have an overall grade of 45, she could make a -151 on her 6th test