Question

A and B can do a task in t hours.A and b can complete the task in t+2 and t+18 hours respectively.Find t

Answer 1

Explanation:

A can do 1/(t+2) of the task in 1 hour.

B can do 1/(t+18) of the task in 1 hour.

t×1/(t+2) + t×1/(t+18) = t/t = 1 (the full task is done)

t + t×(t+2)/(t+18) = t+2

t×(t+18) + t×(t+2) = (t+2)(t+18)

t² + 18t + t² + 2t = t² + 20t + 36

2t² + 20t = t² + 20t + 36

2t² = t² + 36

t² = 36

t = 6