Time and Work
MCQs Math


Question:     Andrew can finish a work in 37 days. Joshua can finish the same work in 38 days while Kenneth can finish the work in 39 days. How long will it take to finish it if they work together?


Correct Answer  12 2862/4331 days or 12.661 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Andrew = 37 days

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

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

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

Here,

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

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

Similarly,

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

∴ The work done by Joshua in 1 day = 1/38

Similarly,

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

∴ The work done by Kenneth in 1 day = 1/39 part

Now, the work done by Andrew, Joshua, and Kenneth together in 1 day

= Andrew's 1 day work + Joshua's 1 day work + Kenneth's 1 day work

= 1/37 + 1/38 + 1/39

= 1482 + 1443 + 1406/54834

= 4331/54834 part of work

This means in 1 day, 4331/54834 part of work is done by Andrew, Joshua and Kenneth working together.

Now, the number of days required to finish 4331/54834 part of work by Andrew, Joshua, and Kenneth working together = 1

∴ the number of days required to finish the whole work (1 work) by Andrew + Joshua + Kenneth together

= 1/4331/54834

= 1 × 54834/4331 = 54834/4331 days

= 12 2862/4331 days = or 12.661 days

Thus, Andrew, Joshua, and Kenneth working together will finish the total work (1 work) in 12 2862/4331 days = or 12.661 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 Andrew = 37 days

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

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

Thus, the number of days required to finish the work by Andrew, Joshua, and Kenneth together = ?

Here a = 37 days

And, b = 38 days

And, c = 39 days

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

The number of days required to finish the work when Andrew, Joshua, and Kenneth working together

= 37 × 38 × 39/37 × 38 + 37 × 39 + 38 × 39 days

= 54834/1406 + 1443 + 1482 days

= 54834/4331 days

= 54834/4331 days

= 12 2862/4331 days or 12.661

Thus, Andrew, Joshua, and Kenneth together will finish the work in 12 2862/4331 days or 12.661 days Answer


Similar Questions

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(2) If Richard can finish the work in 17 days and Mark can finish the same work in 22 days, then in how many days both can finish the work together?

(3) If Barbara can finish the work in 13 days and Anthony can finish the same work in 17 days, then in how many days both can finish the work together?

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(5) If Sarah can finish the work in 22 days and Joshua can finish the same work in 27 days, then in how many days both can finish the work together?

(6) Pamela can finish a work in 78 days. Nicole can finish the same work in 83 days while Helen can finish the work in 88 days. How long will it take to finish it if they work together?

(7) If Elizabeth can finish the work in 11 days and Daniel can finish the same work in 15 days, then in how many days both can finish the work together?

(8) 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?

(9) Kenneth can finish a work in 45 days. Brian can finish the same work in 50 days while George can finish the work in 55 days. How long will it take to finish it if they work together?

(10) Jack can finish a work in 99 days. Jerry can finish the same work in 104 days while Tyler can finish the work in 109 days. How long will it take to finish it if they work together?


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