WAEC - Mathematics (2009 - No. 15)
In an examination, Kofi scored x% in Physics, 50% in Chemistry and 70% in Biology. If his mean score for the three subjects was 55%, find x
40
45
55
60
Explicaţie
\(\frac{x + 50 + 70}{3} = 55\)
x + 120 = 3(55)
x + 120 = 165
= 165 - 120
x = 45%
x + 120 = 3(55)
x + 120 = 165
= 165 - 120
x = 45%