Time and Work
MCQs Math


Question:     Carolyn can finish a work in 96 days. Catherine can finish the same work in 101 days while Maria can finish the work in 106 days. How long will it take to finish it if they work together?


Correct Answer  33 9351/15289 days or 33.612 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Carolyn = 96 days

And, the number of days required to finish the same work by Catherine = 101 days

And, the number of days required to finish the same work by Maria = 106 days

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

Here,

∵ In 96 days the work is done by Carolyn = 1

∴ The work done by Carolyn in 1 day = 1/96

Similarly,

∵ In 101 days the work is done by Catherine = 1

∴ The work done by Catherine in 1 day = 1/101

Similarly,

∵ In 106 days the work is done by Maria = 1

∴ The work done by Maria in 1 day = 1/106 part

Now, the work done by Carolyn, Catherine, and Maria together in 1 day

= Carolyn's 1 day work + Catherine's 1 day work + Maria's 1 day work

= 1/96 + 1/101 + 1/106

= 5353 + 5088 + 4848/513888

= 15289/513888 part of work

This means in 1 day, 15289/513888 part of work is done by Carolyn, Catherine and Maria working together.

Now, the number of days required to finish 15289/513888 part of work by Carolyn, Catherine, and Maria working together = 1

∴ the number of days required to finish the whole work (1 work) by Carolyn + Catherine + Maria together

= 1/15289/513888

= 1 × 513888/15289 = 513888/15289 days

= 33 9351/15289 days = or 33.612 days

Thus, Carolyn, Catherine, and Maria working together will finish the total work (1 work) in 33 9351/15289 days = or 33.612 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 Carolyn = 96 days

And the number of days required to finish the same work by Catherine = 101 days

And the number of days required to finish the work by Maria = 106 days

Thus, the number of days required to finish the work by Carolyn, Catherine, and Maria together = ?

Here a = 96 days

And, b = 101 days

And, c = 106 days

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

The number of days required to finish the work when Carolyn, Catherine, and Maria working together

= 96 × 101 × 106/96 × 101 + 96 × 106 + 101 × 106 days

= 1027776/9696 + 10176 + 10706 days

= 1027776/30578 days

= 1027776/30578 days

= 1027776 ÷ 2/30578 ÷ 2 = 513888/15289 days

= 33 9351/15289 days or 33.612

Thus, Carolyn, Catherine, and Maria together will finish the work in 33 9351/15289 days or 33.612 days Answer


Similar Questions

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