JAMB - Mathematics (2003 - No. 34)
The result of tossing a fair die 120 times is summarized above. Find the value of x
19
20
21
22
Explication
12 + 20 + x + 21 + x-1 +28 = 120
2x + 80 = 120
2x = 120 - 80
2x = 40
x = 20
2x + 80 = 120
2x = 120 - 80
2x = 40
x = 20