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

(1) If Cynthia can finish the work in 64 days and Walter can finish the same work in 69 days, then in how many days both can finish the work together?

(2) If Elizabeth can finish the work in 14 days and Daniel can finish the same work in 19 days, then in how many days both can finish the work together?

(3) Sandra can finish a work in 30 days. Ashley can finish the same work in 31 days while Kimberly can finish the work in 32 days. How long will it take to finish it if they work together?

(4) If Sharon can finish the work in 60 days and Zachary can finish the same work in 65 days, then in how many days both can finish the work together?

(5) Laura can finish a work in 62 days. Kathleen can finish the same work in 67 days while Amy can finish the work in 72 days. How long will it take to finish it if they work together?

(6) If Joseph can finish the work in 16 days and Steven can finish the same work in 19 days, then in how many days both can finish the work together?

(7) If Samantha can finish the work in 86 days and Logan can finish the same work in 91 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) Jack can finish a work in 99 days. Jerry can finish the same work in 104 days while Tyler can finish the work in 109 days. How long will it take to finish it if they work together?

(10) If Deborah can finish the work in 54 days and Aaron can finish the same work in 59 days, then in how many days both can finish the work together?


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