Question

Three typists working for 8 hours a day type a document in 10 days.If only 2 typists are working,how many hours a day should they work to finish the job in 12 days?

Answer 1

the job takes 3*8*10=240 typist-hours. 

2 typists working x hours per day perform 2x typist-hours per day. 

So, 2x*12 = 240 
x = 10 hours per day

Answer 2

Hi there!

Let the required time be = x hours

Given :- 3 Typist can type a doc. in 8 hours
 
Now,

♦ Typists decrease then hours will get increased :-

So, x = 8 × 3 / 2

♦ More days means then less hours would be required :-

So, x = 8 × 10 / 12

Finally,
The hours needed = x = 8 × 3 / 2 × 10 / 12 = 240 / 24 = 10 hours
 

Hence, The required answer is :- 10 hours

Hope it helps! :)