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) Rachel can finish a work in 94 days. Janet can finish the same work in 99 days while Catherine can finish the work in 104 days. How long will it take to finish it if they work together?

(2) Patricia can finish a work in 4 days. Jennifer can finish the same work in 5 days while Linda can finish the work in 6 days. How long will it take to finish it if they work together?

(3) If Robert can finish a work in 4 days and Bob can finish the same work in 6 days, then in how many days they both can finish the work working together?

(4) If Richard can finish the work in 36 days and Mark can finish the same work in 52 days, then in how many days both can finish the work together?

(5) If Benjamin can finish the work in 85 days and Gabriel can finish the same work in 90 days, then in how many days both can finish the work together?

(6) If Justin can finish the work in 79 days and Jesse can finish the same work in 84 days, then in how many days both can finish the work together?

(7) Joseph can finish a work in 15 days. Thomas can finish the same work in 16 days while Charles can finish the work in 17 days. How long will it take to finish it if they work together?

(8) If Steven can finish the work in 37 days and Jonathan can finish the same work in 42 days, then in how many days both can finish the work together?

(9) Barbara can finish a work in 12 days. Susan can finish the same work in 13 days while Jessica can finish the work in 14 days. How long will it take to finish it if they work together?

(10) Jeffrey can finish a work in 61 days. Jacob can finish the same work in 66 days while Gary can finish the work in 71 days. How long will it take to finish it if they work together?


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