5 men can prepare 10 toys in 6 days working 6 hours per day. In how many days can 12 men prepare 16 toys working 8 hours per day?

5 men in 6 days in 6 hours per day$$=5\times 6\times 6=180$$hours

Therefore, 180 hours will be taken to produce 10 toys 

Therefore 1 toy$$=\dfrac {180}{10}=18$$hours

16 toys can be prepare in$$=16\times 18=288$$hours

When,12 men prepare 16 toys$$=\dfrac {288}{12}=24$$hours per day

Then by working 8 hours per day it will be$$=\dfrac {24}{8}=3$$days

Therefore in 3 days 12 men can prepare 16  toys for working 8 hours a day.