Question

A and B can do a piece of work in 20 days .If A alone can do the whole work in 36 days in how many days will B finish the work alone

Answer 1

Answer:

45 days

Step-by-step explanation:

LCM between 20 and 36 gives tota units of work - 180 Units

A + B per day - 180/20 - 9 Units

A per day -180/36- 5 Units

B per day - 9-5 - 4 units

No. of days - 180/4-45 days

Answer 2

Answer:

Work done by A in 36 days = 1

work done by A in 1 day = 1/36

work done by A & B in 20 days = 1

work done by A&B in 1 day = 1/20

So work done by B in 1 day = 1/20-1/36= 1/45

Now, Time taken by B to complete 1/45 work = 1 day

so Time taken by B to complete 1 work = 1÷ 1/45 = 45 days