Question

Jack can program an app in 3 hours. Chris can program the same app in 8 hours. How long would it take them to program the same app working together?

Answer 1

2 2/11 hours

Explanation:

Let the number of hours

Jack spent programming his app = J

Chris spent programming his app = C

Total hours if they worked together = T

Hence,

1/T = 1/3 + 1/8

Lowest Common Denominator = 34

1/T = 8 + 3/24

1/T = 11/24

Cross Multiply

T × 11 = 1 × 24

T = 24/11

T = 2 2/11 hours

Therefore, it would take them to program 2 2/11 hours to program the same app working together