Question

Unitary Method
6. A and B can do a piece of work in 12 days,
B and C in 15 days and C
and A in
20 days. When they work together, the
time required will be
(a) 10 days
(b) 12 days
(c) 13 days
(d) 15 days
7. A bus needs 30 L of diesel for running
120 km distance How many kilometres​

Answer 1

Step-by-step explanation:

Given A and B do piace of work in 12 days and B and C in 15 days and C and A in 20 days

Then A and B one day work = 1/12

AND B and C one day work = 1/15

And C and A one day work = 1/2

NOW, Then A ,B and c two days work = 1/12+1/15+1/20

= 5+4+3/60

= 12/60

= 1/5 DAY

Then A ,B and c one days work= 1/5×1/2

= 1/10

THEREFORE A,B and C do work in 10 days

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