In an examination, Kofi scored x% in Physics, 50% in Chemistry and 70% in Biology.
MATHEMATICS
WAEC 2009
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
- A. 40
- B. 45
- C. 55
- D. 60
Correct Answer: B. 45
Explanation
\(\frac{x + 50 + 70}{3} = 55\)
x + 120 = 3(55)
x + 120 = 165
= 165 - 120
x = 45%
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