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

(1) If Mark can finish the work in 30 days and Jacob can finish the same work in 34 days, then in how many days both can finish the work together?

(2) If Brian can finish the work in 46 days and Raymond can finish the same work in 50 days, then in how many days both can finish the work together?

(3) Thomas can finish a work in 21 days. Christopher can finish the same work in 26 days while Daniel can finish the work in 31 days. How long will it take to finish it if they work together?

(4) If Dorothy can finish the work in 47 days and Jack can finish the same work in 51 days, then in how many days both can finish the work together?

(5) If Paul can finish the work in 36 days and Larry can finish the same work in 39 days, then in how many days both can finish the work together?

(6) If Robert can finish a work in 4 days and Bob can finish the same work in 6 days, then in how many days they both can finish the work working together?

(7) David can finish a work in 13 days. Richard can finish the same work in 18 days while Joseph can finish the work in 23 days. How long will it take to finish it if they work together?

(8) If David can finish the work in 13 days and Christopher can finish the same work in 18 days, then in how many days both can finish the work together?

(9) If Myra can finish the work in 25 days and Sophia can finish the same work in 15 days, then in how many days they both can finish the work working together?

(10) If Edward can finish the work in 57 days and Nathan can finish the same work in 62 days, then in how many days both can finish the work together?


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