In a class of 10 boys and 15 girls, the average score in ...
In a class of 10 boys and 15 girls, the average score in a Biology test is 90. If the average score for the girls is x, find the average score for the boys in terms of x.
200−2x3
225−3x2
250−2x
250−3x
Correct answer is B
Let A and B be the sum for the boys and girls respectively.
A+B10+15=A+B25=90
⟹A+B=90×25=2250
Given the average for girls = x, we have \(\frac{B}{15} = x \implies B = 15x)
∴ average score for boys = \frac{2250 - 15x}{10}
= 225 - \frac{3x}{2}
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