Time and Work
MCQs Math


Question:     Mary can finish a work in 6 days. Jennifer can finish the same work in 11 days while Linda can finish the work in 16 days. How long will it take to finish it if they work together?


Correct Answer  3 21/169 days or 3.124 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Mary = 6 days

And, the number of days required to finish the same work by Jennifer = 11 days

And, the number of days required to finish the same work by Linda = 16 days

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

Here,

∵ In 6 days the work is done by Mary = 1

∴ The work done by Mary in 1 day = 1/6

Similarly,

∵ In 11 days the work is done by Jennifer = 1

∴ The work done by Jennifer in 1 day = 1/11

Similarly,

∵ In 16 days the work is done by Linda = 1

∴ The work done by Linda in 1 day = 1/16 part

Now, the work done by Mary, Jennifer, and Linda together in 1 day

= Mary's 1 day work + Jennifer's 1 day work + Linda's 1 day work

= 1/6 + 1/11 + 1/16

= 88 + 48 + 33/528

= 169/528 part of work

This means in 1 day, 169/528 part of work is done by Mary, Jennifer and Linda working together.

Now, the number of days required to finish 169/528 part of work by Mary, Jennifer, and Linda working together = 1

∴ the number of days required to finish the whole work (1 work) by Mary + Jennifer + Linda together

= 1/169/528

= 1 × 528/169 = 528/169 days

= 3 21/169 days = or 3.124 days

Thus, Mary, Jennifer, and Linda working together will finish the total work (1 work) in 3 21/169 days = or 3.124 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 Mary = 6 days

And the number of days required to finish the same work by Jennifer = 11 days

And the number of days required to finish the work by Linda = 16 days

Thus, the number of days required to finish the work by Mary, Jennifer, and Linda together = ?

Here a = 6 days

And, b = 11 days

And, c = 16 days

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

The number of days required to finish the work when Mary, Jennifer, and Linda working together

= 6 × 11 × 16/6 × 11 + 6 × 16 + 11 × 16 days

= 1056/66 + 96 + 176 days

= 1056/338 days

= 1056/338 days

= 1056 ÷ 2/338 ÷ 2 = 528/169 days

= 3 21/169 days or 3.124

Thus, Mary, Jennifer, and Linda together will finish the work in 3 21/169 days or 3.124 days Answer


Similar Questions

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(2) If Joshua can finish the work in 40 days and Benjamin can finish the same work in 43 days, then in how many days both can finish the work together?

(3) George can finish a work in 51 days. Ronald can finish the same work in 56 days while Edward can finish the work in 61 days. How long will it take to finish it if they work together?

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(6) If Scott can finish the work in 81 days and Bryan can finish the same work in 86 days, then in how many days both can finish the work together?

(7) Lisa can finish a work in 22 days. Nancy can finish the same work in 23 days while Betty can finish the work in 24 days. How long will it take to finish it if they work together?

(8) Daniel can finish a work in 23 days. Matthew can finish the same work in 24 days while Anthony can finish the work in 25 days. How long will it take to finish it if they work together?

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