Time and Work
MCQs Math


Question:     Kimberly can finish a work in 38 days. Donna can finish the same work in 43 days while Michelle can finish the work in 48 days. How long will it take to finish it if they work together?


Correct Answer  14 562/2761 days or 14.204 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Kimberly = 38 days

And, the number of days required to finish the same work by Donna = 43 days

And, the number of days required to finish the same work by Michelle = 48 days

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

Here,

∵ In 38 days the work is done by Kimberly = 1

∴ The work done by Kimberly in 1 day = 1/38

Similarly,

∵ In 43 days the work is done by Donna = 1

∴ The work done by Donna in 1 day = 1/43

Similarly,

∵ In 48 days the work is done by Michelle = 1

∴ The work done by Michelle in 1 day = 1/48 part

Now, the work done by Kimberly, Donna, and Michelle together in 1 day

= Kimberly's 1 day work + Donna's 1 day work + Michelle's 1 day work

= 1/38 + 1/43 + 1/48

= 1032 + 912 + 817/39216

= 2761/39216 part of work

This means in 1 day, 2761/39216 part of work is done by Kimberly, Donna and Michelle working together.

Now, the number of days required to finish 2761/39216 part of work by Kimberly, Donna, and Michelle working together = 1

∴ the number of days required to finish the whole work (1 work) by Kimberly + Donna + Michelle together

= 1/2761/39216

= 1 × 39216/2761 = 39216/2761 days

= 14 562/2761 days = or 14.204 days

Thus, Kimberly, Donna, and Michelle working together will finish the total work (1 work) in 14 562/2761 days = or 14.204 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 Kimberly = 38 days

And the number of days required to finish the same work by Donna = 43 days

And the number of days required to finish the work by Michelle = 48 days

Thus, the number of days required to finish the work by Kimberly, Donna, and Michelle together = ?

Here a = 38 days

And, b = 43 days

And, c = 48 days

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

The number of days required to finish the work when Kimberly, Donna, and Michelle working together

= 38 × 43 × 48/38 × 43 + 38 × 48 + 43 × 48 days

= 78432/1634 + 1824 + 2064 days

= 78432/5522 days

= 78432/5522 days

= 78432 ÷ 2/5522 ÷ 2 = 39216/2761 days

= 14 562/2761 days or 14.204

Thus, Kimberly, Donna, and Michelle together will finish the work in 14 562/2761 days or 14.204 days Answer


Similar Questions

(1) Steven can finish a work in 37 days. Andrew can finish the same work in 42 days while Joshua can finish the work in 47 days. How long will it take to finish it if they work together?

(2) If Sharon can finish the work in 60 days and Zachary can finish the same work in 65 days, then in how many days both can finish the work together?

(3) Melissa can finish a work in 48 days. Deborah can finish the same work in 49 days while Stephanie can finish the work in 50 days. How long will it take to finish it if they work together?

(4) If Robert can finish a work in 5 days and Bob can finish the same work in 6 days, then in how many days they both can finish the work working together?

(5) If Catherine can finish the work in 100 days and Mason can finish the same work in 105 days, then in how many days both can finish the work together?

(6) If Emma can finish the work in 80 days and Jordan can finish the same work in 85 days, then in how many days both can finish the work together?

(7) If David can finish the work in 32 days and Christopher can finish the same work in 48 days, then in how many days both can finish the work together?

(8) If Matthew can finish the work in 26 days and Edward can finish the same work in 29 days, then in how many days both can finish the work together?

(9) If Kimberly can finish the work in 35 days and Stephen can finish the same work in 39 days, then in how many days both can finish the work together?

(10) 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?


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