Time and Work
MCQs Math


Question:     Sarah can finish a work in 22 days. Lisa can finish the same work in 27 days while Nancy can finish the work in 32 days. How long will it take to finish it if they work together?


Correct Answer  8 856/1081 days or 8.792 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Sarah = 22 days

And, the number of days required to finish the same work by Lisa = 27 days

And, the number of days required to finish the same work by Nancy = 32 days

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

Here,

∵ In 22 days the work is done by Sarah = 1

∴ The work done by Sarah in 1 day = 1/22

Similarly,

∵ In 27 days the work is done by Lisa = 1

∴ The work done by Lisa in 1 day = 1/27

Similarly,

∵ In 32 days the work is done by Nancy = 1

∴ The work done by Nancy in 1 day = 1/32 part

Now, the work done by Sarah, Lisa, and Nancy together in 1 day

= Sarah's 1 day work + Lisa's 1 day work + Nancy's 1 day work

= 1/22 + 1/27 + 1/32

= 432 + 352 + 297/9504

= 1081/9504 part of work

This means in 1 day, 1081/9504 part of work is done by Sarah, Lisa and Nancy working together.

Now, the number of days required to finish 1081/9504 part of work by Sarah, Lisa, and Nancy working together = 1

∴ the number of days required to finish the whole work (1 work) by Sarah + Lisa + Nancy together

= 1/1081/9504

= 1 × 9504/1081 = 9504/1081 days

= 8 856/1081 days = or 8.792 days

Thus, Sarah, Lisa, and Nancy working together will finish the total work (1 work) in 8 856/1081 days = or 8.792 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 Sarah = 22 days

And the number of days required to finish the same work by Lisa = 27 days

And the number of days required to finish the work by Nancy = 32 days

Thus, the number of days required to finish the work by Sarah, Lisa, and Nancy together = ?

Here a = 22 days

And, b = 27 days

And, c = 32 days

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

The number of days required to finish the work when Sarah, Lisa, and Nancy working together

= 22 × 27 × 32/22 × 27 + 22 × 32 + 27 × 32 days

= 19008/594 + 704 + 864 days

= 19008/2162 days

= 19008/2162 days

= 19008 ÷ 2/2162 ÷ 2 = 9504/1081 days

= 8 856/1081 days or 8.792

Thus, Sarah, Lisa, and Nancy together will finish the work in 8 856/1081 days or 8.792 days Answer


Similar Questions

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(2) If Thomas can finish the work in 18 days and Andrew can finish the same work in 21 days, then in how many days both can finish the work together?

(3) If Dorothy can finish the work in 47 days and Jack can finish the same work in 51 days, then in how many days both can finish the work together?

(4) Jason can finish a work in 59 days. Ryan can finish the same work in 64 days while Jacob can finish the work in 69 days. How long will it take to finish it if they work together?

(5) If Lisa can finish the work in 23 days and George can finish the same work in 26 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) If Sandra can finish the work in 31 days and Gary can finish the same work in 35 days, then in how many days both can finish the work together?

(8) If Sarah can finish the work in 19 days and Joshua can finish the same work in 23 days, then in how many days both can finish the work together?

(9) If Charles can finish the work in 20 days and Kenneth can finish the same work in 24 days, then in how many days both can finish the work together?

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