Eighteen persons working 8 hours a day can complete 3 units of work in 10 days. How many days are required by 25 persons to complete 5 units of work working 6 hours a day?

16

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 = Units of Work,

⇒ Putting in the values,

⇒ $\frac{18\;×\;10\;×\;8}{25\;×\;D_2\;×\;6}$= $\frac{3}{5}$

⇒ ${ D}_{2 }$ = 16 days.