Time and Work
MCQs Math


Question:     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?


Correct Answer  18 4386/4861 days or 18.902 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Melissa = 52 days

And, the number of days required to finish the same work by Stephanie = 57 days

And, the number of days required to finish the same work by Rebecca = 62 days

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

Here,

∵ In 52 days the work is done by Melissa = 1

∴ The work done by Melissa in 1 day = 1/52

Similarly,

∵ In 57 days the work is done by Stephanie = 1

∴ The work done by Stephanie in 1 day = 1/57

Similarly,

∵ In 62 days the work is done by Rebecca = 1

∴ The work done by Rebecca in 1 day = 1/62 part

Now, the work done by Melissa, Stephanie, and Rebecca together in 1 day

= Melissa's 1 day work + Stephanie's 1 day work + Rebecca's 1 day work

= 1/52 + 1/57 + 1/62

= 1767 + 1612 + 1482/91884

= 4861/91884 part of work

This means in 1 day, 4861/91884 part of work is done by Melissa, Stephanie and Rebecca working together.

Now, the number of days required to finish 4861/91884 part of work by Melissa, Stephanie, and Rebecca working together = 1

∴ the number of days required to finish the whole work (1 work) by Melissa + Stephanie + Rebecca together

= 1/4861/91884

= 1 × 91884/4861 = 91884/4861 days

= 18 4386/4861 days = or 18.902 days

Thus, Melissa, Stephanie, and Rebecca working together will finish the total work (1 work) in 18 4386/4861 days = or 18.902 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 Melissa = 52 days

And the number of days required to finish the same work by Stephanie = 57 days

And the number of days required to finish the work by Rebecca = 62 days

Thus, the number of days required to finish the work by Melissa, Stephanie, and Rebecca together = ?

Here a = 52 days

And, b = 57 days

And, c = 62 days

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

The number of days required to finish the work when Melissa, Stephanie, and Rebecca working together

= 52 × 57 × 62/52 × 57 + 52 × 62 + 57 × 62 days

= 183768/2964 + 3224 + 3534 days

= 183768/9722 days

= 183768/9722 days

= 183768 ÷ 2/9722 ÷ 2 = 91884/4861 days

= 18 4386/4861 days or 18.902

Thus, Melissa, Stephanie, and Rebecca together will finish the work in 18 4386/4861 days or 18.902 days Answer


Similar Questions

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(2) If Raymond can finish the work in 97 days and Eugene can finish the same work in 102 days, then in how many days both can finish the work together?

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(6) If Patricia can finish the work in 5 days and William can finish the same work in 8 days, then in how many days both can finish the work together?

(7) If Kimberly can finish the work in 35 days and Stephen can finish the same work in 38 days, then in how many days both can finish the work together?

(8) Deborah can finish a work in 50 days. Stephanie can finish the same work in 51 days while Rebecca can finish the work in 52 days. How long will it take to finish it if they work together?

(9) If Jessica can finish the work in 20 days and Paul can finish the same work in 25 days, then in how many days both can finish the work together?

(10) If Steven can finish the work in 34 days and Jonathan can finish the same work in 38 days, then in how many days both can finish the work together?


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