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

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(2) 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?

(3) If Donald can finish the work in 32 days and Nicholas can finish the same work in 36 days, then in how many days both can finish the work together?

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(5) If Emily can finish the work in 40 days and Justin can finish the same work in 45 days, then in how many days both can finish the work together?

(6) If Betty can finish the work in 27 days and Jason can finish the same work in 31 days, then in how many days both can finish the work together?

(7) 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?

(8) Samuel can finish a work in 87 days. Alexander can finish the same work in 92 days while Frank can finish the work in 97 days. How long will it take to finish it if they work together?

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