Time and Work
MCQs Math


Question:     Richard can finish a work in 17 days. Thomas can finish the same work in 22 days while Charles can finish the work in 27 days. How long will it take to finish it if they work together?


Correct Answer  7 109/1427 days or 7.076 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Richard = 17 days

And, the number of days required to finish the same work by Thomas = 22 days

And, the number of days required to finish the same work by Charles = 27 days

Thus, the number of days required to finish the work by all of them if they work together = ?

Here,

∵ In 17 days the work is done by Richard = 1

∴ The work done by Richard in 1 day = 1/17

Similarly,

∵ In 22 days the work is done by Thomas = 1

∴ The work done by Thomas in 1 day = 1/22

Similarly,

∵ In 27 days the work is done by Charles = 1

∴ The work done by Charles in 1 day = 1/27 part

Now, the work done by Richard, Thomas, and Charles together in 1 day

= Richard's 1 day work + Thomas's 1 day work + Charles's 1 day work

= 1/17 + 1/22 + 1/27

= 594 + 459 + 374/10098

= 1427/10098 part of work

This means in 1 day, 1427/10098 part of work is done by Richard, Thomas and Charles working together.

Now, the number of days required to finish 1427/10098 part of work by Richard, Thomas, and Charles working together = 1

∴ the number of days required to finish the whole work (1 work) by Richard + Thomas + Charles together

= 1/1427/10098

= 1 × 10098/1427 = 10098/1427 days

= 7 109/1427 days = or 7.076 days

Thus, Richard, Thomas, and Charles working together will finish the total work (1 work) in 7 109/1427 days = or 7.076 days Answer

Shortcut Trick to solve the problems based on time and work using formula

Case: If A can finish a work in a days, B can finish the same work in b days, and C can finish the work in c days
then working together the number of days required to finish the work
= a × b × c/ab + ac + bc days.

Here given,

The number of days required to finish the work by Richard = 17 days

And the number of days required to finish the same work by Thomas = 22 days

And the number of days required to finish the work by Charles = 27 days

Thus, the number of days required to finish the work by Richard, Thomas, and Charles together = ?

Here a = 17 days

And, b = 22 days

And, c = 27 days

Thus, using formula a × b × c/ab + ac + bc days

The number of days required to finish the work when Richard, Thomas, and Charles working together

= 17 × 22 × 27/17 × 22 + 17 × 27 + 22 × 27 days

= 10098/374 + 459 + 594 days

= 10098/1427 days

= 10098/1427 days

= 7 109/1427 days or 7.076

Thus, Richard, Thomas, and Charles together will finish the work in 7 109/1427 days or 7.076 days Answer


Similar Questions

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(2) If Robert can finish the work in 7 days and David can finish the same work in 12 days, then in how many days both can finish the work together?

(3) If Robert can finish the work in 4 days and David can finish the same work in 8 days, then in how many days both can finish the work together?

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(6) If Eric can finish the work in 71 days and Gerald can finish the same work in 76 days, then in how many days both can finish the work together?

(7) Cynthia can finish a work in 64 days. Amy can finish the same work in 69 days while Angela can finish the work in 74 days. How long will it take to finish it if they work together?

(8) Margaret can finish a work in 28 days. Sandra can finish the same work in 29 days while Ashley can finish the work in 30 days. How long will it take to finish it if they work together?

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