If 8 men working 8 hours per day for 8 days produces 64 chairs, then how many chairs 4 men will produce working 4 hours per day for 4 days?

6 8 12 10

8

Formula used: \(\frac{M_1\;×\;D_1\;×\;H_1\;×\;E_1}{E_2\;×\;D_2\;×\;H_2\;×\;E_2}\) = \(\frac{W_1}{W_2}\) efficiency of all the men is same, E₁ = E₂ ⇒ \(\frac{8\;×\;8\;×\;8}{4\;×\;4\;×\;4}\) = \(\frac{64}{W_2}\) ⇒       W₂ = 8 chairs