15 boys can complete a task in 28 days. In how many days can 21 boys complete the same task?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 20.
We know that
M1 × D1 × H1 = M2 × D2 × H2
here, M = Mens, D = days, and H = Hours
Now, according to the question
⇒ 15 × 28 = 21 × D
⇒ D = (15 × 28)/21
⇒ D = 20 days