Question

Three boys and five girls together can finish a job in 3 days. Working on the same job 3 girls take 5 days more than the time required by 2 men. What is the ratio of efficiency of a boy to a girl?

• A. 2: 1
• B. 5: 2
• C. 3: 2
• D. 4: 1

Answer 1

The correct option is B

5: 2

$3B+5G=33.33\%..............\left(i\right)$

Time taken by 3 women $=\frac{100}{3G}$ ; Time taken by 2 men $=\frac{100}{2B}$

$\frac{100}{3G}-\frac{100}{2B}=5\to \frac{33.33}{G}-\frac{50}{B}=5.................\left(ii\right)$

Option (a): B=2G $\to$ 11G = 33.33$\%$ $\to$ G = 3.03 , B = 6.06. Substitute in (ii), 11 - (approx 8) = approx 3.

Option (b): B=2.5G $\to$ 12.5G = 33.33$\%$ $\to$ G = $\frac{8}{3}$ , B=$\frac{20}{3}$, Substitute in (ii), 12.5 - 7.5 = 5 which is the difference given in the question.Hence option (b).