Question

52. P can complete a work in 12
days working 8 hours a day,
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?
​

Answer 1

P takes 12 days to complete a work working 8hr per day,

P can complete work in 12days×8hr/day=96hr...

similarly,

Q completes work in 8×10=80hr....

P's 1hour work =1/96

Q's 1hour work =1/80..hence

(P+Q)'s 1hour work=[(1/96)+(1/80)]

=11/480

so,(P+Q) together can complete work in 480/11 hours...

given (P+Q) work 8hr per day..

1day-------------------->8hr they work

'x'days-----------------> (480/11)hr

on cross multiplication,

x=60/11days

=5 5/11 days