Newton, Einstein, and Tesla working alone can do a piece of work in 20, 30, and 60 days respectively. All three of them start the work together, but after x days Newton leaves and then after y more days Einstein leaves and Tesla completes the remaining work. If Einstein had not left, Tesla and Einstein would have completed the remaining work in (y + 6) days after Newton had left. If both Newton and Einstein had stayed, the work would have been completed in (x + 6) days. What is the total number of days taken to complete the work?

Newton, Einstein, and Tesla working alone can do a piece of work in 20, 30, and 60 days respectively. All three of them start the work together, but after x days Newton leaves and then after y more days Einstein leaves and Tesla completes the remaining work. If Einstein had not left, Tesla and Einstein would have completed the remaining work in (y + 6) days after Newton had left. If both Newton and Einstein had stayed, the work would have been completed in (x + 6) days. What is the total number of days taken to complete the work? Correct Answer 28

Given:

Newton’s Time = 20 days

Einstein’s Time = 30 days

Tesla’s Time = 60 days

All three together time = (x + 6) days

Calculation:

The data provides three different combinations of working, to do the work completely.

1) Combination 1 -

All three people working for(x+6) days.

(1/20 + 1/30 + 1/60) = 1/(x + 6)

⇒ (6/60) = 1/(x + 6)

⇒ x + 6 = 10

⇒ x = 4 days

2) Combination 2 -

All three people for x days,and two people for(y + 6) days.

(x)/10 + (y + 6)(1/30 + 1/60) = 1

Substituting x=4,

⇒ 4/10 + (y + 6)(1/20) = 1

⇒ (y + 6)(1/20) = 1 – 4/10

⇒ y + 6 = 12

⇒ y = 6

3) Combination 3 –

All three for x days, two people for y days and one person for z days.

x(1/10) + y(1/20) + z/60 = 1

Substituting x=4,y = 6, and simplifying,

⇒ z/60 = 1 – 4/10 –6/20

⇒ z/60 = 3/10

⇒ z = 18 days

∴ Total number of days required under combination 3, is

x + y + z = 4 + 6 + 18 = 28 days

Alternate Method –

1. A, B and C four days work = 4 × 6 = 24

Left work = 60 - 24 = 36

(B + C) complete left work in Time = 36/3 = 12

Y + 6 = 12

Y = 6

2. (B + C) 6 days work 6 × 3 = 18

work left = 60 – 24 – 18 - 18

C = 18 /1 =18 days

Total time = A + B + C = 4 + 6 = 28 days

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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.