An experienced accountant can prepare a tax return in 13 hours. A novice accountant can do the job in 19 hours. How long will it take them to do the job working

Question

the last part is together 

Answer 1

The experienced can prepare 1/13th of the tax return per hour, the novice 1/19th per hour.

In 2 hours, they will have 2/13th plus 2/19th completed, etc.

 

We can write (1/13th) X + (1/19th) X = 1,

where X is the number of hours.

 

Find a common denominator, and multiply, and we get:

(19/247) X + (13/247) X = 1

(32/247) X = 1

X = 7.72 hours