Time and Work - General Aptitude

Q1:

P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both P and Q work together, working 8 hours a day, in how many days can they complete the work?

A
5 5
11

B
5 6
11

C
6 5
11

D
6 6
11

ANS:A -

5 5
11

P can complete the work in (12 x 8) hrs. = 96 hrs. Q can complete the work in (8 x 10) hrs. = 80 hrs.

 P's1 hour's work = 1 and Q's 1 hour's work = 1 .
96 80
(P + Q)'s 1 hour's work = 1 + 1 = 11 .
96 80 480
So, both P and Q will finish the work in 480 hrs.
11
 Number of days of 8 hours each = 480 x 1 = 60 days = 5 5 days.
11 8 11 11