If 72 boys can build a wall of 280 m length in 21 days, how many boys would take 18 days to build a similar type of wall of length 200 m ? - Quantitative Aptitude MCQ Adda247 2026 | ExamTest.live

mediumMCQAdda2472026Quantitative Aptitude

1 mark

If 72 boys can build a wall of 280 m length in 21 days, how many boys would take 18 days to build a similar type of wall of length 200 m ?

Solution & Step-by-step Explanation

We can use the work-man-days formula: \frac{M _{1} \times D _{1}}{W _{1}} = \frac{M _{2} \times D _{2}}{W _{2}} Given: M_{1} = 72 D_{1} = 21 W_{1} = 280 m D_{2} = 18 W_{2} = 200 m M_{2} = ? Substituting the values into the formula: \frac{72 \times 21}{280} = \frac{M _{2} \times 18}{200} Simplifying the left-hand side: \frac{72 \times 3}{40} = \frac{M _{2} \times 18}{200} \frac{9 \times 3}{5} = \frac{18 \times M _{2}}{200} \frac{27}{5} = \frac{18 \times M _{2}}{200} Solving for M_{2} : M_{2} = \frac{27 \times 200}{5 \times 18} M_{2} = \frac{27 \times 40}{18} M_{2} = \frac{3 \times 40}{2} = 60 boys

Try it yourself before checking the explanation above.

If 72 boys can build a wall of 280 m length in 21 days, how many boys would take 18 days to build a similar type of wall of length 200 m ?

40 boys

48 boys

28 boys

60 boys

Practice with timed mock tests and track your performance across Quantitative Aptitude.