Question

$90$ men can complete a work in $24$ days working $8$ hours a day. How many men are required to complete the same working in $18$ days working $7\frac{1}{2}$ hours a day ?

• A. $112$ men
• B. $128$ men
• C. $140$ men
• D. $133$ men

Answer 1

The correct option is B $128$ men

Let $x$ men complete the same work in $18$ days working for $7\frac{1}{2}$ hours, which $90$ men complete in $24$ days and $8$ hours a day.
$90\times 24\times 8=x\times 18\times \frac{15}{2}$
$⟹x=\frac{90\times 24\times \times 2}{18\times 15}$

$x=128$ men.