Time and Work
MCQs Math


Question:     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?


Correct Answer  22 6554/7129 days or 22.919 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Cynthia = 64 days

And, the number of days required to finish the same work by Amy = 69 days

And, the number of days required to finish the same work by Angela = 74 days

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

Here,

∵ In 64 days the work is done by Cynthia = 1

∴ The work done by Cynthia in 1 day = 1/64

Similarly,

∵ In 69 days the work is done by Amy = 1

∴ The work done by Amy in 1 day = 1/69

Similarly,

∵ In 74 days the work is done by Angela = 1

∴ The work done by Angela in 1 day = 1/74 part

Now, the work done by Cynthia, Amy, and Angela together in 1 day

= Cynthia's 1 day work + Amy's 1 day work + Angela's 1 day work

= 1/64 + 1/69 + 1/74

= 2553 + 2368 + 2208/163392

= 7129/163392 part of work

This means in 1 day, 7129/163392 part of work is done by Cynthia, Amy and Angela working together.

Now, the number of days required to finish 7129/163392 part of work by Cynthia, Amy, and Angela working together = 1

∴ the number of days required to finish the whole work (1 work) by Cynthia + Amy + Angela together

= 1/7129/163392

= 1 × 163392/7129 = 163392/7129 days

= 22 6554/7129 days = or 22.919 days

Thus, Cynthia, Amy, and Angela working together will finish the total work (1 work) in 22 6554/7129 days = or 22.919 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 Cynthia = 64 days

And the number of days required to finish the same work by Amy = 69 days

And the number of days required to finish the work by Angela = 74 days

Thus, the number of days required to finish the work by Cynthia, Amy, and Angela together = ?

Here a = 64 days

And, b = 69 days

And, c = 74 days

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

The number of days required to finish the work when Cynthia, Amy, and Angela working together

= 64 × 69 × 74/64 × 69 + 64 × 74 + 69 × 74 days

= 326784/4416 + 4736 + 5106 days

= 326784/14258 days

= 326784/14258 days

= 326784 ÷ 2/14258 ÷ 2 = 163392/7129 days

= 22 6554/7129 days or 22.919

Thus, Cynthia, Amy, and Angela together will finish the work in 22 6554/7129 days or 22.919 days Answer


Similar Questions

(1) If Kenneth can finish the work in 42 days and Gregory can finish the same work in 46 days, then in how many days both can finish the work together?

(2) If Kimberly can finish the work in 38 days and Stephen can finish the same work in 43 days, then in how many days both can finish the work together?

(3) 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?

(4) Rebecca can finish a work in 58 days. Laura can finish the same work in 63 days while Cynthia can finish the work in 68 days. How long will it take to finish it if they work together?

(5) George can finish a work in 51 days. Ronald can finish the same work in 56 days while Edward can finish the work in 61 days. How long will it take to finish it if they work together?

(6) If Linda can finish the work in 31 days and Charles can finish the same work in 47 days, then in how many days both can finish the work together?

(7) Matthew can finish a work in 29 days. Mark can finish the same work in 34 days while Donald can finish the work in 39 days. How long will it take to finish it if they work together?

(8) Emily can finish a work in 36 days. Donna can finish the same work in 37 days while Michelle can finish the work in 38 days. How long will it take to finish it if they work together?

(9) If Sarah can finish the work in 19 days and Joshua can finish the same work in 22 days, then in how many days both can finish the work together?

(10) If Michael can finish the work in 30 days and Thomas can finish the same work in 46 days, then in how many days both can finish the work together?


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