Juan can complete a job in 12 days and Berto can do the same job in 6 days.hiw many days will it take the two men to complete the job if they work together?

Question

Rational Algebraic Expression

 

Answer 1

(1/12) + (1/6) = (1/x) 

3/12 = 1/x

x= 4

 

Now why?

The reciprocals are rates.

If x = the time they both work when working together:

 

x/12 is the amount of the job Juan does and x/6 is the amount of the job Berto does and together they do the whole job.

This means (x/12) + (x/6) = 1 which results in the equation with which I started.