If Ava can finish a job in 6 hours and Kim can do the same job in 5 hours then how long would it take them to finish the same job if they worked together?

Question

A. 5.5

B. 2 8/11

C. 2                                 These are the choices for the answers.

D. 1 4/5

E. 1

Answer 1

Ava/s work rate is 1/6 of whole job per hour. Kim's rate per hour if 1/5.

 

If they work t hours together, and complete the whole job, then t(1/6) + t(1/5) = 1.

 

Solve for t.  Hint: factor out t and combine the two fractions by using a common denominator.