Time and Work
MCQs Math


Question:     Shirley can finish a work in 72 days. Brenda can finish the same work in 77 days while Pamela can finish the work in 82 days. How long will it take to finish it if they work together?


Correct Answer  25 5279/8881 days or 25.594 days

Solution And Explanation

Solution

Given,

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

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

And, the number of days required to finish the same work by Pamela = 82 days

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

Here,

∵ In 72 days the work is done by Shirley = 1

∴ The work done by Shirley in 1 day = 1/72

Similarly,

∵ In 77 days the work is done by Brenda = 1

∴ The work done by Brenda in 1 day = 1/77

Similarly,

∵ In 82 days the work is done by Pamela = 1

∴ The work done by Pamela in 1 day = 1/82 part

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

= Shirley's 1 day work + Brenda's 1 day work + Pamela's 1 day work

= 1/72 + 1/77 + 1/82

= 3157 + 2952 + 2772/227304

= 8881/227304 part of work

This means in 1 day, 8881/227304 part of work is done by Shirley, Brenda and Pamela working together.

Now, the number of days required to finish 8881/227304 part of work by Shirley, Brenda, and Pamela working together = 1

∴ the number of days required to finish the whole work (1 work) by Shirley + Brenda + Pamela together

= 1/8881/227304

= 1 × 227304/8881 = 227304/8881 days

= 25 5279/8881 days = or 25.594 days

Thus, Shirley, Brenda, and Pamela working together will finish the total work (1 work) in 25 5279/8881 days = or 25.594 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 Shirley = 72 days

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

And the number of days required to finish the work by Pamela = 82 days

Thus, the number of days required to finish the work by Shirley, Brenda, and Pamela together = ?

Here a = 72 days

And, b = 77 days

And, c = 82 days

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

The number of days required to finish the work when Shirley, Brenda, and Pamela working together

= 72 × 77 × 82/72 × 77 + 72 × 82 + 77 × 82 days

= 454608/5544 + 5904 + 6314 days

= 454608/17762 days

= 454608/17762 days

= 454608 ÷ 2/17762 ÷ 2 = 227304/8881 days

= 25 5279/8881 days or 25.594

Thus, Shirley, Brenda, and Pamela together will finish the work in 25 5279/8881 days or 25.594 days Answer


Similar Questions

(1) If Kevin can finish the work in 44 days and Frank can finish the same work in 48 days, then in how many days both can finish the work together?

(2) 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?

(3) If Rebecca can finish the work in 58 days and Henry can finish the same work in 63 days, then in how many days both can finish the 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?

(5) If Joseph can finish the work in 19 days and Steven can finish the same work in 24 days, then in how many days both can finish the work together?

(6) Anna can finish a work in 74 days. Pamela can finish the same work in 79 days while Emma can finish the work in 84 days. How long will it take to finish it if they work together?

(7) Cynthia can finish a work in 64 days. Amy can finish the same work in 69 days while Angela can finish the work in 74 days. How long will it take to finish it if they work together?

(8) Steven can finish a work in 33 days. Paul can finish the same work in 34 days while Andrew can finish the work in 35 days. How long will it take to finish it if they work together?

(9) If Daniel can finish the work in 24 days and Timothy can finish the same work in 27 days, then in how many days both can finish the work together?

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