A alone can complete a work in 10 days, B alone can complete the same work in 20 days and C alone can complete the same work in 15 days. A and C work together for some time and left, If B worked for 10 days to complete the work, then A and C worked for how many days?

A alone can complete a work in 10 days, B alone can complete the same work in 20 days and C alone can complete the same work in 15 days. A and C work together for some time and left, If B worked for 10 days to complete the work, then A and C worked for how many days? Correct Answer 3 days

Given:

A alone can complete a work in 10 days.

B alone can complete the same work in 20 days.

C alone can complete the same work in 15 days.

Formula:

Total work = Efficiency × Time

Calculation:

Total work = 60 units  (LCM of 10, 20 and 15)

Efficiency of A = 6 units/day

Efficiency of B = 3 units/day

Efficiency of C = 4 units/day

Let A and C worked for x, days

According to the question

(6 + 4) × x + 3 × 10 = 60

⇒ 10x = 60 – 30

⇒ 10x = 30

⇒ x = 30/10

⇒ x = 3 days

∴ A and C work for 3 days.

Related Questions

Each question below is followed by two statements I and II. You have to determine whether the data given in the statement is sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer. P, Q and R together can complete a work in 12 days. All of them worked together for 6 days and then P left. How much time will Q and R together will take to complete the remaining work? I. If P completes a work in X number of days, then Q and R together complete the work in X number of days. II. After leaving the work, P completed another work in 10 days.