Question 40607
it takes 4 hours for 9 cooks to prepare a school lunch. How long would it take 6 cooks to prepare the lunch?

9 cooks = 1 lunch/4hr.
Multiply thru by 6/9 to get 6 cooks on the left side, as follows:

(6/9)9 cooks = (6/9)(1lunch)/4hr.
Rearrange the right side to get:

6 cooks = (1 lunch)/ [4hr.*(9/6)]
6 cooks = 1 lunch/ [4hr*(3/2)]
6 cooks = 1 lunch/ 6 hr.
Cheers,
Stan H.