Question

10 men, working 6 hours a day can complete a work in 18 days. how many hours a day must 15 men work to complete the work in 12 days ?

Answer 1

let the required numbers of hours per day be x.
More men, less hours per day. (inverse proportion)
Men= 15:10
Days= 12:18::6:x

=> 15 X 12 X x= 10 X 18 X 6
=>10 X 18 X 6/ (15 X 12)
x=6

Answer 2

Answer:

6 hours a day must 15 men work to complete the same work in 12 days.

Step-by-step explanation:

Given :10 men, working. 6 hours a day can complete a work in 18 days.

To Find :how many hours a day must 15 men work to complete the work in 12 days ?

Solution:

$Formula :\frac{m_1 \times h_1 \times d_1}{w_1} =\frac{m_2 \times h_2 \times d_2}{w_2}$

$w_1=1\\m_1 =10\\h_1=6\\d_1=18\\w_2=1\\h_2=x\\m_2=15\\d_2=12$

Substitute the values in the formula :

$\frac{10 \times 6 \times 18}{1} =\frac{15 \times x \times 12}{1}\\\\\frac{10 \times 6 \times 18}{15 \times 12} =x \\\\6=x$

Hence 6 hours a day must 15 men work to complete the same work in 12 days.