Question 61081
Suppose the time taken by the Canon machine to complete the job = x hrs.
So time taken by the HP machine = 2x hrs.

Quantity copied by the canon in 1 hr = 1/x
Quantity copied by the HP in 1 hr = 1/2x

Together the quantity copied in 1 hr = 1/x + 1/2x
                                      = (2+1)/2x [taking LCD]
                                      = 3/2x

Given the time taken by both to complete the job = 24 min
==> quantity copied in 1 hr = 1/24

Equating we get,
1/24 = 3/2x
multiply both the sides by 24x(LCD),
(1/24)(24x) = (3/2x)(24x)
==> x = 36

Thus the Canon takes 36 minto copy and the HP takes 36*2  = 72 min to copy.


Good Luck!!!