Twenty girls and y boys sat on an examination. The mean marks obtained by the girls and boys were 52 and 57 respectively. if the total score for both girls and boys was 2750, find y.
A. 51 B. 48 C. 30 D. 25 E. 18
Correct Answer: C
Explanation
Let the total score for the girls and the boys be A and B respectively. \(\frac{A}{20} = 52 \implies A = 52 \times 20\) A = 1040 \(\frac{B}{y} = 57 \implies B = 57y\) 1040 + 57y = 2750 57y = 2750 - 1040 57y = 1710 y = \(\frac{1710}{57}\) y = 30
