8 men can make 12 chairs in 12 days if they work for 6 hours a day. If 9 chairs are to be make by 12 men in 6 days, then how many hours a day does each one of them need to work?

6 hours

Formula to be used here,

\(\frac{M_1\;×\;D_1\;×\;H_1}{M_2\;×\;D_2\;×\;H_2}\) = \(\frac{W_1}{W_2}\)

where, M = No. of Men, D = No. of Days, H = No. of hours, W = Work,

⇒ Putting values in the formula,

⇒ \(\frac{8\;×\;12\;×\;6}{12\;×\;6\;×\;H_2}\) = \(\frac{12}{9}\)

⇒ \( { H}_{2 } \) = 6 hours.