Question

vincent’s copier can print in 7 hours. chris’s printer can do the same in 13 hours. how long would it take to do the job using both copiers

Answer 1

Explanation:

1/7+1/13=1/t

multiply both sides by 7*13*t

13t+7t=7*13

21t=91

t=91/19

it will take 4 hours and 8 minutes