Question

Selma's class is making care packages to give to victims of a natural disaster. Selma packs one box in 5 minutes and has already packed 12 boxes. Her friend Trudy packs one box in 7 minutes and has already packed 18 boxes. How many more minutes does each need to work in order to have packed the same number of boxes?

Answer 1

66 more min. he used which could be 1 hour and 6 min.

Answer 2

Selma      Trudy

12 + x/5 = 18 + x/7    (x = amount of time, in minutes)

x/5 - x/7 = 18 - 12

7x/35-5x/35=6

35*6/2=105 minutes

%282x%29%2F35%29%29 = 6  ====>  x = %2835%2A6%29%2F2 = 105 minutes.

Answer.  105 minutes,  or 1 hour and 45 minutes.