Time and Work
MCQs Math


Question:     Elizabeth can finish a work in 14 days. Susan can finish the same work in 19 days while Jessica can finish the work in 24 days. How long will it take to finish it if they work together?


Correct Answer  6 18/529 days or 6.034 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Elizabeth = 14 days

And, the number of days required to finish the same work by Susan = 19 days

And, the number of days required to finish the same work by Jessica = 24 days

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

Here,

∵ In 14 days the work is done by Elizabeth = 1

∴ The work done by Elizabeth in 1 day = 1/14

Similarly,

∵ In 19 days the work is done by Susan = 1

∴ The work done by Susan in 1 day = 1/19

Similarly,

∵ In 24 days the work is done by Jessica = 1

∴ The work done by Jessica in 1 day = 1/24 part

Now, the work done by Elizabeth, Susan, and Jessica together in 1 day

= Elizabeth's 1 day work + Susan's 1 day work + Jessica's 1 day work

= 1/14 + 1/19 + 1/24

= 228 + 168 + 133/3192

= 529/3192 part of work

This means in 1 day, 529/3192 part of work is done by Elizabeth, Susan and Jessica working together.

Now, the number of days required to finish 529/3192 part of work by Elizabeth, Susan, and Jessica working together = 1

∴ the number of days required to finish the whole work (1 work) by Elizabeth + Susan + Jessica together

= 1/529/3192

= 1 × 3192/529 = 3192/529 days

= 6 18/529 days = or 6.034 days

Thus, Elizabeth, Susan, and Jessica working together will finish the total work (1 work) in 6 18/529 days = or 6.034 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 Elizabeth = 14 days

And the number of days required to finish the same work by Susan = 19 days

And the number of days required to finish the work by Jessica = 24 days

Thus, the number of days required to finish the work by Elizabeth, Susan, and Jessica together = ?

Here a = 14 days

And, b = 19 days

And, c = 24 days

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

The number of days required to finish the work when Elizabeth, Susan, and Jessica working together

= 14 × 19 × 24/14 × 19 + 14 × 24 + 19 × 24 days

= 6384/266 + 336 + 456 days

= 6384/1058 days

= 6384/1058 days

= 6384 ÷ 2/1058 ÷ 2 = 3192/529 days

= 6 18/529 days or 6.034

Thus, Elizabeth, Susan, and Jessica together will finish the work in 6 18/529 days or 6.034 days Answer


Similar Questions

(1) Charles can finish a work in 23 days. Daniel can finish the same work in 28 days while Matthew can finish the work in 33 days. How long will it take to finish it if they work together?

(2) Timothy can finish a work in 49 days. Ronald can finish the same work in 50 days while Edward can finish the work in 51 days. How long will it take to finish it if they work together?

(3) Emily can finish a work in 40 days. Michelle can finish the same work in 45 days while Carol can finish the work in 50 days. How long will it take to finish it if they work together?

(4) 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?

(5) Kenneth can finish a work in 45 days. Brian can finish the same work in 50 days while George can finish the work in 55 days. How long will it take to finish it if they work together?

(6) Justin can finish a work in 79 days. Brandon can finish the same work in 84 days while Benjamin can finish the work in 89 days. How long will it take to finish it if they work together?

(7) If Elizabeth can finish the work in 11 days and Daniel can finish the same work in 14 days, then in how many days both can finish the work together?

(8) If Lisa can finish the work in 23 days and George can finish the same work in 27 days, then in how many days both can finish the work together?

(9) Anthony can finish a work in 31 days. Donald can finish the same work in 36 days while Steven can finish the work in 41 days. How long will it take to finish it if they work together?

(10) If Brandon can finish the work in 83 days and Joe can finish the same work in 88 days, then in how many days both can finish the work together?


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