Time and Work
MCQs Math


Question:     Sandra can finish a work in 34 days. Kimberly can finish the same work in 39 days while Emily can finish the work in 44 days. How long will it take to finish it if they work together?


Correct Answer  12 1944/2269 days or 12.857 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Sandra = 34 days

And, the number of days required to finish the same work by Kimberly = 39 days

And, the number of days required to finish the same work by Emily = 44 days

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

Here,

∵ In 34 days the work is done by Sandra = 1

∴ The work done by Sandra in 1 day = 1/34

Similarly,

∵ In 39 days the work is done by Kimberly = 1

∴ The work done by Kimberly in 1 day = 1/39

Similarly,

∵ In 44 days the work is done by Emily = 1

∴ The work done by Emily in 1 day = 1/44 part

Now, the work done by Sandra, Kimberly, and Emily together in 1 day

= Sandra's 1 day work + Kimberly's 1 day work + Emily's 1 day work

= 1/34 + 1/39 + 1/44

= 858 + 748 + 663/29172

= 2269/29172 part of work

This means in 1 day, 2269/29172 part of work is done by Sandra, Kimberly and Emily working together.

Now, the number of days required to finish 2269/29172 part of work by Sandra, Kimberly, and Emily working together = 1

∴ the number of days required to finish the whole work (1 work) by Sandra + Kimberly + Emily together

= 1/2269/29172

= 1 × 29172/2269 = 29172/2269 days

= 12 1944/2269 days = or 12.857 days

Thus, Sandra, Kimberly, and Emily working together will finish the total work (1 work) in 12 1944/2269 days = or 12.857 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 Sandra = 34 days

And the number of days required to finish the same work by Kimberly = 39 days

And the number of days required to finish the work by Emily = 44 days

Thus, the number of days required to finish the work by Sandra, Kimberly, and Emily together = ?

Here a = 34 days

And, b = 39 days

And, c = 44 days

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

The number of days required to finish the work when Sandra, Kimberly, and Emily working together

= 34 × 39 × 44/34 × 39 + 34 × 44 + 39 × 44 days

= 58344/1326 + 1496 + 1716 days

= 58344/4538 days

= 58344/4538 days

= 58344 ÷ 2/4538 ÷ 2 = 29172/2269 days

= 12 1944/2269 days or 12.857

Thus, Sandra, Kimberly, and Emily together will finish the work in 12 1944/2269 days or 12.857 days Answer


Similar Questions

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(2) 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?

(3) Jessica can finish a work in 16 days. Sarah can finish the same work in 17 days while Karen can finish the work in 18 days. How long will it take to finish it if they work together?

(4) If Ashley can finish the work in 33 days and Eric can finish the same work in 37 days, then in how many days both can finish the work together?

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(6) If Richard can finish the work in 14 days and Mark can finish the same work in 18 days, then in how many days both can finish the work together?

(7) Barbara can finish a work in 16 days. Jessica can finish the same work in 21 days while Sarah can finish the work in 26 days. How long will it take to finish it if they work together?

(8) Brian can finish a work in 45 days. George can finish the same work in 46 days while Timothy can finish the work in 47 days. How long will it take to finish it if they work together?

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