Question

6 men or 10 boys can complete a piece of work in 15 days. if 7 men and x boys complete the same piece of work in 9 days, then x is equal to

• A. 4
• B. 5
• C. 6
• D. 7

Answer 1

Answer: (B)

5

6 men = 10 boys $\Rightarrow$ 1 man = $\frac{10}{6}$ boys $\Rightarrow$ 7 men = $(\frac{10}{6}\times 7)$ boys = $\frac{35}{3}$ boys
10 boys can complete the work in 15 days $\Rightarrow$ 1 boy can complete the work in (10 x 15) days $(\frac{35}{3}+x)$
boys can complete the work in 9 days $\Rightarrow$ 1 boy can complete the work in $(\frac{35}{3}+x)\times 9$ days
$\therefore$ 10 x 15 = $(\frac{35}{3}+x)\times 9$ $\Rightarrow$ 9x = 150 - 105 = 45 $\Rightarrow$ x = 5