Question

A,Band C can do a piece of work in 15,12 and 20 days respectively. they started the work together, but C left after 2 days. in how many days will the remaining work be completed by A and B?​

Answer 1

★Given:-

• A,Band C can do a piece of work in 15,12 and 20 days respectively.

• They started working together
• C left after 2 days

★To find:-

• In how many days will the remaining work be completed by A and B?​

★Solution:-

Given that,

No of days taken to do a piece of work by,

• A = 15days
• B = 12days
• C = 20 days

Then,

Work done in 1 day by,

• A = 1/15
• B = 1/12
• C = 1/20

Total work done together in 1 day:-

⇒(1/15)+(1/12)+(1/20)

⇒ (4+5+3)/60

⇒ 12/60

⇒ 1/5

Total work done together in 2days:-

⇒2×1/5

⇒ 2/5

Work done by A&B in 1day:-

⇒ 1/15 + 1/12

⇒ 3/20

Remaining work:-

⇒ 1 -2/5

⇒ 3/5

Let work is done by A&B in x days

Then,

No.of.days taken by A&B to complete the remaining work:-

⇒(Remaining work)÷(Combined work of A&B)

⇒ (3/5) ÷ (3/20)

⇒ 20 / 5

⇒ 4days.

Hence,

The remaining work will be completed by A & B in 4 days.

_______________

Answer 2

Answer:

Correct Question:-

1. A, B and C can do work in 20, 15 and 12 days. A is assisted by B on first day and by C on the next day alternatively. How long the work would be take to finish?

Given as,

A – 20

B – 15

C – 12

Solution:-

➪ A + B

= 3 + 4

➪A + C

= 5 + 3

2 days × 4 = 8 days

15 unit × 4 = 60 units