Time and Work
MCQs Math


Question:     Nancy can finish a work in 24 days. Betty can finish the same work in 25 days while Margaret can finish the work in 26 days. How long will it take to finish it if they work together?


Correct Answer  8 304/937 days or 8.324 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Nancy = 24 days

And, the number of days required to finish the same work by Betty = 25 days

And, the number of days required to finish the same work by Margaret = 26 days

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

Here,

∵ In 24 days the work is done by Nancy = 1

∴ The work done by Nancy in 1 day = 1/24

Similarly,

∵ In 25 days the work is done by Betty = 1

∴ The work done by Betty in 1 day = 1/25

Similarly,

∵ In 26 days the work is done by Margaret = 1

∴ The work done by Margaret in 1 day = 1/26 part

Now, the work done by Nancy, Betty, and Margaret together in 1 day

= Nancy's 1 day work + Betty's 1 day work + Margaret's 1 day work

= 1/24 + 1/25 + 1/26

= 325 + 312 + 300/7800

= 937/7800 part of work

This means in 1 day, 937/7800 part of work is done by Nancy, Betty and Margaret working together.

Now, the number of days required to finish 937/7800 part of work by Nancy, Betty, and Margaret working together = 1

∴ the number of days required to finish the whole work (1 work) by Nancy + Betty + Margaret together

= 1/937/7800

= 1 × 7800/937 = 7800/937 days

= 8 304/937 days = or 8.324 days

Thus, Nancy, Betty, and Margaret working together will finish the total work (1 work) in 8 304/937 days = or 8.324 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 Nancy = 24 days

And the number of days required to finish the same work by Betty = 25 days

And the number of days required to finish the work by Margaret = 26 days

Thus, the number of days required to finish the work by Nancy, Betty, and Margaret together = ?

Here a = 24 days

And, b = 25 days

And, c = 26 days

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

The number of days required to finish the work when Nancy, Betty, and Margaret working together

= 24 × 25 × 26/24 × 25 + 24 × 26 + 25 × 26 days

= 15600/600 + 624 + 650 days

= 15600/1874 days

= 15600/1874 days

= 15600 ÷ 2/1874 ÷ 2 = 7800/937 days

= 8 304/937 days or 8.324

Thus, Nancy, Betty, and Margaret together will finish the work in 8 304/937 days or 8.324 days Answer


Similar Questions

(1) If Lisa can finish the work in 23 days and George can finish the same work in 26 days, then in how many days both can finish the work together?

(2) If Sandra can finish the work in 34 days and Gary can finish the same work in 39 days, then in how many days both can finish the work together?

(3) If Emily can finish the work in 37 days and Justin can finish the same work in 41 days, then in how many days both can finish the work together?

(4) If Andrew can finish the work in 41 days and Scott can finish the same work in 46 days, then in how many days both can finish the work together?

(5) Anna can finish a work in 74 days. Pamela can finish the same work in 79 days while Emma can finish the work in 84 days. How long will it take to finish it if they work together?

(6) If James can finish the work in 2 days and John can finish the same work in 5 days, then in how many days both can finish the work together?

(7) If Jessica can finish the work in 17 days and Paul can finish the same work in 21 days, then in how many days both can finish the work together?

(8) Nancy can finish a work in 24 days. Betty can finish the same work in 25 days while Margaret can finish the work in 26 days. How long will it take to finish it if they work together?

(9) 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?

(10) Donald can finish a work in 31 days. Steven can finish the same work in 32 days while Paul can finish the work in 33 days. How long will it take to finish it if they work together?


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