Time and Work
MCQs Math


Question:     Emily can finish a work in 40 days. Michelle can finish the same work in 45 days while Carol can finish the work in 50 days. How long will it take to finish it if they work together?


Correct Answer  14 106/121 days or 14.876 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Emily = 40 days

And, the number of days required to finish the same work by Michelle = 45 days

And, the number of days required to finish the same work by Carol = 50 days

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

Here,

∵ In 40 days the work is done by Emily = 1

∴ The work done by Emily in 1 day = 1/40

Similarly,

∵ In 45 days the work is done by Michelle = 1

∴ The work done by Michelle in 1 day = 1/45

Similarly,

∵ In 50 days the work is done by Carol = 1

∴ The work done by Carol in 1 day = 1/50 part

Now, the work done by Emily, Michelle, and Carol together in 1 day

= Emily's 1 day work + Michelle's 1 day work + Carol's 1 day work

= 1/40 + 1/45 + 1/50

= 45 + 40 + 36/1800

= 121/1800 part of work

This means in 1 day, 121/1800 part of work is done by Emily, Michelle and Carol working together.

Now, the number of days required to finish 121/1800 part of work by Emily, Michelle, and Carol working together = 1

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

= 1/121/1800

= 1 × 1800/121 = 1800/121 days

= 14 106/121 days = or 14.876 days

Thus, Emily, Michelle, and Carol working together will finish the total work (1 work) in 14 106/121 days = or 14.876 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 Emily = 40 days

And the number of days required to finish the same work by Michelle = 45 days

And the number of days required to finish the work by Carol = 50 days

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

Here a = 40 days

And, b = 45 days

And, c = 50 days

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

The number of days required to finish the work when Emily, Michelle, and Carol working together

= 40 × 45 × 50/40 × 45 + 40 × 50 + 45 × 50 days

= 90000/1800 + 2000 + 2250 days

= 90000/6050 days

= 90000/6050 days

= 90000 ÷ 50/6050 ÷ 50 = 1800/121 days

= 14 106/121 days or 14.876

Thus, Emily, Michelle, and Carol together will finish the work in 14 106/121 days or 14.876 days Answer


Similar Questions

(1) 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?

(2) Barbara can finish a work in 16 days. Jessica can finish the same work in 21 days while Sarah can finish the work in 26 days. How long will it take to finish it if they work together?

(3) If Steven can finish the work in 37 days and Jonathan can finish the same work in 42 days, then in how many days both can finish the work together?

(4) Debra can finish a work in 92 days. Carolyn can finish the same work in 97 days while Janet can finish the work in 102 days. How long will it take to finish it if they work together?

(5) Melissa can finish a work in 52 days. Stephanie can finish the same work in 57 days while Rebecca can finish the work in 62 days. How long will it take to finish it if they work together?

(6) Brandon can finish a work in 83 days. Samuel can finish the same work in 88 days while Gregory can finish the work in 93 days. How long will it take to finish it if they work together?

(7) Susan can finish a work in 18 days. Sarah can finish the same work in 23 days while Karen can finish the work in 28 days. How long will it take to finish it if they work together?

(8) Lisa can finish a work in 26 days. Betty can finish the same work in 31 days while Margaret can finish the work in 36 days. How long will it take to finish it if they work together?

(9) If Brandon can finish the work in 83 days and Joe can finish the same work in 88 days, then in how many days both can finish the work together?

(10) Kimberly can finish a work in 34 days. Emily can finish the same work in 35 days while Donna can finish the work in 36 days. How long will it take to finish it if they work together?


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