Time and Work
MCQs Math


Question:     If Shirley can finish the work in 72 days and Harold can finish the same work in 77 days, then in how many days both can finish the work together?


Correct Answer  37 31/149 days or 37.208 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Shirley = 72 days

And, the number of days to finish the same work by Harold = 77 days

Thus, the number of days to finish the work by Shirley and Harold together = ?

Here,

∵ In 72 days the work done by Shirley = 1

∴ In 1 day, the work done by Shirley = 1/72 part

Similarly,

∵ In 77 days the work done by Harold = 1

∴ In 1 day, the work done by Harold = 1/77 part

Now, in 1 day, the work done by Shirley and Harold together

= In 1 day work done by Shirley + In 1 day the work done by Harold

= 1/72 + 1/77

= 77 + 72/5544

= 149/5544 part of work

This means in 1 day, 149/5544 part of work is done by Shirley and Harold working together.

Now, the number of days required to finish 149/5544 part of work by Shirley + Harold working together = 1

∴ the number of days required to finish 1 work by Shirley + Harold together

= 1/149/5544

= 1 × 5544/149 = 5544/149 days

= 37 31/149 days = or 37.208 days

Thus, Shirley and Harold working together will finish the work in 37 31/149 days = or 37.208 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, and B can finish the same work in b days,
then working together the number of days require to finish the work
= a × b/a + b days.

Here given,

The number of days required to finish the work by Shirley = 72 days

And the number of days required to finish the same work by Harold = 77 days

Thus, the number of days required to finish the work Shirley and Harold working together = ?

Here a = 72 days

And, b = 77 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Shirley and Harold working together

= 72 × 77/72 + 77 days

= 5544/149 days

= 37 31/149 days or 37.208

Thus, Shirley and Harold together will finish the work in 37 31/149 days or 37.208 days Answer


Similar Questions

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(2) If Joseph can finish the work in 16 days and Steven can finish the same work in 20 days, then in how many days both can finish the work together?

(3) Patricia can finish a work in 8 days. Linda can finish the same work in 13 days while Elizabeth can finish the work in 18 days. How long will it take to finish it if they work together?

(4) Anthony can finish a work in 31 days. Donald can finish the same work in 36 days while Steven can finish the work in 41 days. How long will it take to finish it if they work together?

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(6) If Kevin can finish the work in 44 days and Frank can finish the same work in 47 days, then in how many days both can finish the work together?

(7) If Donna can finish the work in 42 days and Brandon can finish the same work in 47 days, then in how many days both can finish the work together?

(8) 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?

(9) Michael can finish a work in 7 days. David can finish the same work in 8 days while William can finish the work in 9 days. How long will it take to finish it if they work together?

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