Time and Work
MCQs Math


Question:     Raymond can finish a work in 97 days. Dennis can finish the same work in 102 days while Jerry can finish the work in 107 days. How long will it take to finish it if they work together?


Correct Answer  33 29487/31187 days or 33.945 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Raymond = 97 days

And, the number of days required to finish the same work by Dennis = 102 days

And, the number of days required to finish the same work by Jerry = 107 days

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

Here,

∵ In 97 days the work is done by Raymond = 1

∴ The work done by Raymond in 1 day = 1/97

Similarly,

∵ In 102 days the work is done by Dennis = 1

∴ The work done by Dennis in 1 day = 1/102

Similarly,

∵ In 107 days the work is done by Jerry = 1

∴ The work done by Jerry in 1 day = 1/107 part

Now, the work done by Raymond, Dennis, and Jerry together in 1 day

= Raymond's 1 day work + Dennis's 1 day work + Jerry's 1 day work

= 1/97 + 1/102 + 1/107

= 10914 + 10379 + 9894/1058658

= 31187/1058658 part of work

This means in 1 day, 31187/1058658 part of work is done by Raymond, Dennis and Jerry working together.

Now, the number of days required to finish 31187/1058658 part of work by Raymond, Dennis, and Jerry working together = 1

∴ the number of days required to finish the whole work (1 work) by Raymond + Dennis + Jerry together

= 1/31187/1058658

= 1 × 1058658/31187 = 1058658/31187 days

= 33 29487/31187 days = or 33.945 days

Thus, Raymond, Dennis, and Jerry working together will finish the total work (1 work) in 33 29487/31187 days = or 33.945 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 Raymond = 97 days

And the number of days required to finish the same work by Dennis = 102 days

And the number of days required to finish the work by Jerry = 107 days

Thus, the number of days required to finish the work by Raymond, Dennis, and Jerry together = ?

Here a = 97 days

And, b = 102 days

And, c = 107 days

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

The number of days required to finish the work when Raymond, Dennis, and Jerry working together

= 97 × 102 × 107/97 × 102 + 97 × 107 + 102 × 107 days

= 1058658/9894 + 10379 + 10914 days

= 1058658/31187 days

= 1058658/31187 days

= 33 29487/31187 days or 33.945

Thus, Raymond, Dennis, and Jerry together will finish the work in 33 29487/31187 days or 33.945 days Answer


Similar Questions

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(2) If Michelle can finish the work in 44 days and Samuel can finish the same work in 49 days, then in how many days both can finish the work together?

(3) Daniel can finish a work in 23 days. Matthew can finish the same work in 24 days while Anthony can finish the work in 25 days. How long will it take to finish it if they work together?

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(6) Patrick can finish a work in 95 days. Jack can finish the same work in 100 days while Dennis can finish the work in 105 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 14 days, then in how many days both can finish the work together?

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