Time and Work
MCQs Math


Question:     Brenda can finish a work in 76 days. Emma can finish the same work in 81 days while Nicole can finish the work in 86 days. How long will it take to finish it if they work together?


Correct Answer  26 9154/9829 days or 26.931 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Brenda = 76 days

And, the number of days required to finish the same work by Emma = 81 days

And, the number of days required to finish the same work by Nicole = 86 days

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

Here,

∵ In 76 days the work is done by Brenda = 1

∴ The work done by Brenda in 1 day = 1/76

Similarly,

∵ In 81 days the work is done by Emma = 1

∴ The work done by Emma in 1 day = 1/81

Similarly,

∵ In 86 days the work is done by Nicole = 1

∴ The work done by Nicole in 1 day = 1/86 part

Now, the work done by Brenda, Emma, and Nicole together in 1 day

= Brenda's 1 day work + Emma's 1 day work + Nicole's 1 day work

= 1/76 + 1/81 + 1/86

= 3483 + 3268 + 3078/264708

= 9829/264708 part of work

This means in 1 day, 9829/264708 part of work is done by Brenda, Emma and Nicole working together.

Now, the number of days required to finish 9829/264708 part of work by Brenda, Emma, and Nicole working together = 1

∴ the number of days required to finish the whole work (1 work) by Brenda + Emma + Nicole together

= 1/9829/264708

= 1 × 264708/9829 = 264708/9829 days

= 26 9154/9829 days = or 26.931 days

Thus, Brenda, Emma, and Nicole working together will finish the total work (1 work) in 26 9154/9829 days = or 26.931 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 Brenda = 76 days

And the number of days required to finish the same work by Emma = 81 days

And the number of days required to finish the work by Nicole = 86 days

Thus, the number of days required to finish the work by Brenda, Emma, and Nicole together = ?

Here a = 76 days

And, b = 81 days

And, c = 86 days

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

The number of days required to finish the work when Brenda, Emma, and Nicole working together

= 76 × 81 × 86/76 × 81 + 76 × 86 + 81 × 86 days

= 529416/6156 + 6536 + 6966 days

= 529416/19658 days

= 529416/19658 days

= 529416 ÷ 2/19658 ÷ 2 = 264708/9829 days

= 26 9154/9829 days or 26.931

Thus, Brenda, Emma, and Nicole together will finish the work in 26 9154/9829 days or 26.931 days Answer


Similar Questions

(1) Shirley can finish a work in 72 days. Brenda can finish the same work in 77 days while Pamela can finish the work in 82 days. How long will it take to finish it if they work together?

(2) If Kevin can finish the work in 44 days and Frank can finish the same work in 47 days, then in how many days both can finish the work together?

(3) Emma can finish a work in 80 days. Helen can finish the same work in 85 days while Samantha can finish the work in 90 days. How long will it take to finish it if they work together?

(4) If Linda can finish the work in 9 days and Charles can finish the same work in 12 days, then in how many days both can finish the work together?

(5) Pamela can finish a work in 78 days. Nicole can finish the same work in 83 days while Helen can finish the work in 88 days. How long will it take to finish it if they work together?

(6) Elizabeth can finish a work in 10 days. Barbara can finish the same work in 11 days while Susan can finish the work in 12 days. How long will it take to finish it if they work together?

(7) 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?

(8) Karen can finish a work in 24 days. Nancy can finish the same work in 29 days while Betty can finish the work in 34 days. How long will it take to finish it if they work together?

(9) Margaret can finish a work in 32 days. Ashley can finish the same work in 37 days while Kimberly can finish the work in 42 days. How long will it take to finish it if they work together?

(10) Brenda can finish a work in 76 days. Emma can finish the same work in 81 days while Nicole can finish the work in 86 days. How long will it take to finish it if they work together?


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