A man, a woman and a boy can complete a work in 3, 4 and 12 days, respectively. How many must assist one man and one woman to complete the same work in one day?
Answer & explanation
Correct answer: option 1
Man = 3 days, Woman = 4 days, Boy = 12 days,
Let's take extra people needed as x.
⇒ \(\frac{Total Work}{Total efficiency}\) = Time
⇒ \(\frac{12}{(4 + 3) + x}\) = 1
⇒ 12 = 7 + x
⇒ x = 12 - 7 = 5
Therefore, 5 people are needed to assist one man and one woman to complete the same work in 1 one day.