Time and Work
MCQs Math


Question:     Sandra can finish a work in 34 days. Kimberly can finish the same work in 39 days while Emily can finish the work in 44 days. How long will it take to finish it if they work together?


Correct Answer  12 1944/2269 days or 12.857 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Sandra = 34 days

And, the number of days required to finish the same work by Kimberly = 39 days

And, the number of days required to finish the same work by Emily = 44 days

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

Here,

∵ In 34 days the work is done by Sandra = 1

∴ The work done by Sandra in 1 day = 1/34

Similarly,

∵ In 39 days the work is done by Kimberly = 1

∴ The work done by Kimberly in 1 day = 1/39

Similarly,

∵ In 44 days the work is done by Emily = 1

∴ The work done by Emily in 1 day = 1/44 part

Now, the work done by Sandra, Kimberly, and Emily together in 1 day

= Sandra's 1 day work + Kimberly's 1 day work + Emily's 1 day work

= 1/34 + 1/39 + 1/44

= 858 + 748 + 663/29172

= 2269/29172 part of work

This means in 1 day, 2269/29172 part of work is done by Sandra, Kimberly and Emily working together.

Now, the number of days required to finish 2269/29172 part of work by Sandra, Kimberly, and Emily working together = 1

∴ the number of days required to finish the whole work (1 work) by Sandra + Kimberly + Emily together

= 1/2269/29172

= 1 × 29172/2269 = 29172/2269 days

= 12 1944/2269 days = or 12.857 days

Thus, Sandra, Kimberly, and Emily working together will finish the total work (1 work) in 12 1944/2269 days = or 12.857 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 Sandra = 34 days

And the number of days required to finish the same work by Kimberly = 39 days

And the number of days required to finish the work by Emily = 44 days

Thus, the number of days required to finish the work by Sandra, Kimberly, and Emily together = ?

Here a = 34 days

And, b = 39 days

And, c = 44 days

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

The number of days required to finish the work when Sandra, Kimberly, and Emily working together

= 34 × 39 × 44/34 × 39 + 34 × 44 + 39 × 44 days

= 58344/1326 + 1496 + 1716 days

= 58344/4538 days

= 58344/4538 days

= 58344 ÷ 2/4538 ÷ 2 = 29172/2269 days

= 12 1944/2269 days or 12.857

Thus, Sandra, Kimberly, and Emily together will finish the work in 12 1944/2269 days or 12.857 days Answer


Similar Questions

(1) If Robert can finish the work in 26 days and David can finish the same work in 42 days, then in how many days both can finish the work together?

(2) If Elizabeth can finish the work in 33 days and Daniel can finish the same work in 49 days, then in how many days both can finish the work together?

(3) If Kimberly can finish the work in 38 days and Stephen can finish the same work in 43 days, then in how many days both can finish the work together?

(4) Jacob can finish a work in 65 days. Nicholas can finish the same work in 70 days while Eric can finish the work in 75 days. How long will it take to finish it if they work together?

(5) If Patricia can finish the work in 5 days and William can finish the same work in 9 days, then in how many days both can finish the work together?

(6) 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?

(7) 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?

(8) If Ashley can finish the work in 33 days and Eric can finish the same work in 37 days, then in how many days both can finish the work together?

(9) If Stephen can finish the work in 75 days and Carl can finish the same work in 80 days, then in how many days both can finish the work together?

(10) If John can finish the work in 6 days and Richard can finish the same work in 9 days, then in how many days both can finish the work together?


NCERT Solution and CBSE Notes for class twelve, eleventh, tenth, ninth, seventh, sixth, fifth, fourth and General Math for competitive Exams. ©