Question 990417
Hi there,
Make his third test = 'x'
Fourth test then = x + 1
So adding up the 4 tests
(83 + 72 + x + (x + 1))/4 = 83
Totalling up.
(2x + 156)/4 = 83
(2x + 156) = 83 x 4
2x + 156 = 332
2x = 332 - 156
2x = 176
x = 88
4 scores are:
83,72,88,89.
So, fourth score was 89.
Hope this helps :-)