Question

a person can do a job in 6 day days . another can do the same job in 4days . if they work together, how long do they need to finish the job?

Answer 1

It will take them 2 2/5 days working together

Explanation:

To find the time worked

1/a + 1/b = 1/t

Where a and b are the times worked individually and t is the time worked together

1/4 + 1/6 = 1/t

Multiply each side by 12t to clear the fractions

12t( 1/4 + 1/6 = 1/t)

3t + 2t =12

Combine like terms

5t = 12

Divide by 5

t = 12/5

t = 2 2/5

It will take them 2 2/5 days working together