Time and Work
MCQs Math


Question:     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?


Correct Answer  16 1184/3601 days or 16.329 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Melissa = 48 days

And, the number of days required to finish the same work by Deborah = 49 days

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

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

Here,

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

∴ The work done by Melissa in 1 day = 1/48

Similarly,

∵ In 49 days the work is done by Deborah = 1

∴ The work done by Deborah in 1 day = 1/49

Similarly,

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

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

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

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

= 1/48 + 1/49 + 1/50

= 1225 + 1200 + 1176/58800

= 3601/58800 part of work

This means in 1 day, 3601/58800 part of work is done by Melissa, Deborah and Stephanie working together.

Now, the number of days required to finish 3601/58800 part of work by Melissa, Deborah, and Stephanie working together = 1

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

= 1/3601/58800

= 1 × 58800/3601 = 58800/3601 days

= 16 1184/3601 days = or 16.329 days

Thus, Melissa, Deborah, and Stephanie working together will finish the total work (1 work) in 16 1184/3601 days = or 16.329 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 = 48 days

And the number of days required to finish the same work by Deborah = 49 days

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

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

Here a = 48 days

And, b = 49 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 Melissa, Deborah, and Stephanie working together

= 48 × 49 × 50/48 × 49 + 48 × 50 + 49 × 50 days

= 117600/2352 + 2400 + 2450 days

= 117600/7202 days

= 117600/7202 days

= 117600 ÷ 2/7202 ÷ 2 = 58800/3601 days

= 16 1184/3601 days or 16.329

Thus, Melissa, Deborah, and Stephanie together will finish the work in 16 1184/3601 days or 16.329 days Answer


Similar Questions

(1) If Nancy can finish the work in 25 days and Ronald can finish the same work in 29 days, then in how many days both can finish the work together?

(2) 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?

(3) 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?

(4) If Richard can finish the work in 14 days and Mark can finish the same work in 17 days, then in how many days both can finish the work together?

(5) Betty can finish a work in 30 days. Sandra can finish the same work in 35 days while Ashley can finish the work in 40 days. How long will it take to finish it if they work together?

(6) Mark can finish a work in 33 days. Steven can finish the same work in 38 days while Paul can finish the work in 43 days. How long will it take to finish it if they work together?

(7) If Deborah can finish the work in 54 days and Aaron can finish the same work in 59 days, then in how many days both can finish the work together?

(8) If Michael can finish the work in 8 days and Thomas can finish the same work in 11 days, then in how many days both can finish the work together?

(9) Nancy can finish a work in 24 days. Betty can finish the same work in 25 days while Margaret can finish the work in 26 days. How long will it take to finish it if they work together?

(10) Jessica can finish a work in 16 days. Sarah can finish the same work in 17 days while Karen can finish the work in 18 days. How long will it take to finish it if they work together?


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