1. The ratio of two numbers is 5 : 7 and their H.C.F, is 9. then their L.C.M. is
(a) 35
(b) 315
(c) 63
(d) 81
2. A and B can do a piece of work in 10 days. B and C can do it in 12 days. C can do it in 20 days. How long will A take to do it alone?
(a) 12
(b) 15
(c) 20
(d) 30
3. A does one-third as much work as B in half of the time taken by B. If together they take 15 days to complete a work, then the time taken by B alone to do it would have been
(a) 20
(b) 25
(c) 30
(d) 35
4. A single discount equivalent to discount series 10%, 20% and 30% is
(a) 60%
(b) 50%
(c) 49.6%
(d) 44.6%
