Question

(a) 20 hours
(b) 22 hours
'A' and 'B' can dig a canal in 30 days. They worked for 10 days and then 'B' left. It took 20 more days to
complete the work by ‘A’. How long will 'A' take to dig the canal on his own?
(a) 27 days
(b) 30 days
(c) 33 days
(d) 37 days​

Answer 1

Since A & B work together for 20 days, they complete 2/3 rd of the work.

Remaining 1/3 work is done by A in 20 days.

=> A alone can do full job in 60 days.

A & B together complete the job in 30 days.

=> 60B/(60 + B) = 30

=> 60B = 1800 + 30B

=> 30B = 1800

B = 60

B alone can do the work in 60 days.

:-)

HAVE A NICE DAY  ..