Time and Work
MCQs Math


Question:     Emily can finish a work in 36 days. Donna can finish the same work in 37 days while Michelle can finish the work in 38 days. How long will it take to finish it if they work together?


Correct Answer  12 672/2053 days or 12.327 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Emily = 36 days

And, the number of days required to finish the same work by Donna = 37 days

And, the number of days required to finish the same work by Michelle = 38 days

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

Here,

∵ In 36 days the work is done by Emily = 1

∴ The work done by Emily in 1 day = 1/36

Similarly,

∵ In 37 days the work is done by Donna = 1

∴ The work done by Donna in 1 day = 1/37

Similarly,

∵ In 38 days the work is done by Michelle = 1

∴ The work done by Michelle in 1 day = 1/38 part

Now, the work done by Emily, Donna, and Michelle together in 1 day

= Emily's 1 day work + Donna's 1 day work + Michelle's 1 day work

= 1/36 + 1/37 + 1/38

= 703 + 684 + 666/25308

= 2053/25308 part of work

This means in 1 day, 2053/25308 part of work is done by Emily, Donna and Michelle working together.

Now, the number of days required to finish 2053/25308 part of work by Emily, Donna, and Michelle working together = 1

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

= 1/2053/25308

= 1 × 25308/2053 = 25308/2053 days

= 12 672/2053 days = or 12.327 days

Thus, Emily, Donna, and Michelle working together will finish the total work (1 work) in 12 672/2053 days = or 12.327 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 Emily = 36 days

And the number of days required to finish the same work by Donna = 37 days

And the number of days required to finish the work by Michelle = 38 days

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

Here a = 36 days

And, b = 37 days

And, c = 38 days

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

The number of days required to finish the work when Emily, Donna, and Michelle working together

= 36 × 37 × 38/36 × 37 + 36 × 38 + 37 × 38 days

= 50616/1332 + 1368 + 1406 days

= 50616/4106 days

= 50616/4106 days

= 50616 ÷ 2/4106 ÷ 2 = 25308/2053 days

= 12 672/2053 days or 12.327

Thus, Emily, Donna, and Michelle together will finish the work in 12 672/2053 days or 12.327 days Answer


Similar Questions

(1) If William can finish the work in 34 days and Matthew can finish the same work in 50 days, then in how many days both can finish the work together?

(2) If Barbara can finish the work in 16 days and Anthony can finish the same work in 21 days, then in how many days both can finish the work together?

(3) If Christopher can finish the work in 22 days and Brian can finish the same work in 25 days, then in how many days both can finish the work together?

(4) Timothy can finish a work in 49 days. Ronald can finish the same work in 50 days while Edward can finish the work in 51 days. How long will it take to finish it if they work together?

(5) If David can finish the work in 10 days and Christopher can finish the same work in 13 days, then in how many days both can finish the work together?

(6) Amanda can finish a work in 48 days. Melissa can finish the same work in 53 days while Deborah can finish the work in 58 days. How long will it take to finish it if they work together?

(7) Charles can finish a work in 19 days. Christopher can finish the same work in 20 days while Daniel can finish the work in 21 days. How long will it take to finish it if they work together?

(8) If Nancy can finish the work in 25 days and Ronald can finish the same work in 29 days, then in how many days both can finish the work together?

(9) George can finish a work in 47 days. Timothy can finish the same work in 48 days while Ronald can finish the work in 49 days. How long will it take to finish it if they work together?

(10) 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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