Time and Work
MCQs Math


Question:     Pamela can finish a work in 78 days. Nicole can finish the same work in 83 days while Helen can finish the work in 88 days. How long will it take to finish it if they work together?


Correct Answer  27 6189/10321 days or 27.6 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Pamela = 78 days

And, the number of days required to finish the same work by Nicole = 83 days

And, the number of days required to finish the same work by Helen = 88 days

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

Here,

∵ In 78 days the work is done by Pamela = 1

∴ The work done by Pamela in 1 day = 1/78

Similarly,

∵ In 83 days the work is done by Nicole = 1

∴ The work done by Nicole in 1 day = 1/83

Similarly,

∵ In 88 days the work is done by Helen = 1

∴ The work done by Helen in 1 day = 1/88 part

Now, the work done by Pamela, Nicole, and Helen together in 1 day

= Pamela's 1 day work + Nicole's 1 day work + Helen's 1 day work

= 1/78 + 1/83 + 1/88

= 3652 + 3432 + 3237/284856

= 10321/284856 part of work

This means in 1 day, 10321/284856 part of work is done by Pamela, Nicole and Helen working together.

Now, the number of days required to finish 10321/284856 part of work by Pamela, Nicole, and Helen working together = 1

∴ the number of days required to finish the whole work (1 work) by Pamela + Nicole + Helen together

= 1/10321/284856

= 1 × 284856/10321 = 284856/10321 days

= 27 6189/10321 days = or 27.6 days

Thus, Pamela, Nicole, and Helen working together will finish the total work (1 work) in 27 6189/10321 days = or 27.6 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 Pamela = 78 days

And the number of days required to finish the same work by Nicole = 83 days

And the number of days required to finish the work by Helen = 88 days

Thus, the number of days required to finish the work by Pamela, Nicole, and Helen together = ?

Here a = 78 days

And, b = 83 days

And, c = 88 days

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

The number of days required to finish the work when Pamela, Nicole, and Helen working together

= 78 × 83 × 88/78 × 83 + 78 × 88 + 83 × 88 days

= 569712/6474 + 6864 + 7304 days

= 569712/20642 days

= 569712/20642 days

= 569712 ÷ 2/20642 ÷ 2 = 284856/10321 days

= 27 6189/10321 days or 27.6

Thus, Pamela, Nicole, and Helen together will finish the work in 27 6189/10321 days or 27.6 days Answer


Similar Questions

(1) Elizabeth can finish a work in 10 days. Barbara can finish the same work in 11 days while Susan can finish the work in 12 days. How long will it take to finish it if they work together?

(2) If Alexander can finish the work in 91 days and Wayne can finish the same work in 96 days, then in how many days both can finish the work together?

(3) If Karen can finish the work in 21 days and Kevin can finish the same work in 25 days, then in how many days both can finish the work together?

(4) 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?

(5) If Annie can finish a work in 5 days and Bobby can finish the same work in 10 days, then in how many days they both can finish the work working together?

(6) If Amanda can finish the work in 45 days and Patrick can finish the same work in 49 days, then in how many days both can finish the work together?

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(9) 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?

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