Time and Work
MCQs Math


Question:     Jacob can finish a work in 65 days. Nicholas can finish the same work in 70 days while Eric can finish the work in 75 days. How long will it take to finish it if they work together?


Correct Answer  23 149/587 days or 23.254 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Jacob = 65 days

And, the number of days required to finish the same work by Nicholas = 70 days

And, the number of days required to finish the same work by Eric = 75 days

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

Here,

∵ In 65 days the work is done by Jacob = 1

∴ The work done by Jacob in 1 day = 1/65

Similarly,

∵ In 70 days the work is done by Nicholas = 1

∴ The work done by Nicholas in 1 day = 1/70

Similarly,

∵ In 75 days the work is done by Eric = 1

∴ The work done by Eric in 1 day = 1/75 part

Now, the work done by Jacob, Nicholas, and Eric together in 1 day

= Jacob's 1 day work + Nicholas's 1 day work + Eric's 1 day work

= 1/65 + 1/70 + 1/75

= 210 + 195 + 182/13650

= 587/13650 part of work

This means in 1 day, 587/13650 part of work is done by Jacob, Nicholas and Eric working together.

Now, the number of days required to finish 587/13650 part of work by Jacob, Nicholas, and Eric working together = 1

∴ the number of days required to finish the whole work (1 work) by Jacob + Nicholas + Eric together

= 1/587/13650

= 1 × 13650/587 = 13650/587 days

= 23 149/587 days = or 23.254 days

Thus, Jacob, Nicholas, and Eric working together will finish the total work (1 work) in 23 149/587 days = or 23.254 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 Jacob = 65 days

And the number of days required to finish the same work by Nicholas = 70 days

And the number of days required to finish the work by Eric = 75 days

Thus, the number of days required to finish the work by Jacob, Nicholas, and Eric together = ?

Here a = 65 days

And, b = 70 days

And, c = 75 days

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

The number of days required to finish the work when Jacob, Nicholas, and Eric working together

= 65 × 70 × 75/65 × 70 + 65 × 75 + 70 × 75 days

= 341250/4550 + 4875 + 5250 days

= 341250/14675 days

= 341250/14675 days

= 341250 ÷ 25/14675 ÷ 25 = 13650/587 days

= 23 149/587 days or 23.254

Thus, Jacob, Nicholas, and Eric together will finish the work in 23 149/587 days or 23.254 days Answer


Similar Questions

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(2) If Sarah can finish the work in 19 days and Joshua can finish the same work in 22 days, then in how many days both can finish the work together?

(3) If Margaret can finish the work in 29 days and Ryan can finish the same work in 32 days, then in how many days both can finish the work together?

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(6) James can finish a work in 5 days. John can finish the same work in 10 days while Michael can finish the work in 15 days. How long will it take to finish it if they work together?

(7) 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?

(8) Donald can finish a work in 35 days. Paul can finish the same work in 40 days while Andrew can finish the work in 45 days. How long will it take to finish it if they work together?

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