Time and Work
MCQs Math


Question:     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?


Correct Answer  14 106/121 days or 14.876 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Emily = 40 days

And, the number of days required to finish the same work by Michelle = 45 days

And, the number of days required to finish the same work by Carol = 50 days

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

Here,

∵ In 40 days the work is done by Emily = 1

∴ The work done by Emily in 1 day = 1/40

Similarly,

∵ In 45 days the work is done by Michelle = 1

∴ The work done by Michelle in 1 day = 1/45

Similarly,

∵ In 50 days the work is done by Carol = 1

∴ The work done by Carol in 1 day = 1/50 part

Now, the work done by Emily, Michelle, and Carol together in 1 day

= Emily's 1 day work + Michelle's 1 day work + Carol's 1 day work

= 1/40 + 1/45 + 1/50

= 45 + 40 + 36/1800

= 121/1800 part of work

This means in 1 day, 121/1800 part of work is done by Emily, Michelle and Carol working together.

Now, the number of days required to finish 121/1800 part of work by Emily, Michelle, and Carol working together = 1

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

= 1/121/1800

= 1 × 1800/121 = 1800/121 days

= 14 106/121 days = or 14.876 days

Thus, Emily, Michelle, and Carol working together will finish the total work (1 work) in 14 106/121 days = or 14.876 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 Emily = 40 days

And the number of days required to finish the same work by Michelle = 45 days

And the number of days required to finish the work by Carol = 50 days

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

Here a = 40 days

And, b = 45 days

And, c = 50 days

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

The number of days required to finish the work when Emily, Michelle, and Carol working together

= 40 × 45 × 50/40 × 45 + 40 × 50 + 45 × 50 days

= 90000/1800 + 2000 + 2250 days

= 90000/6050 days

= 90000/6050 days

= 90000 ÷ 50/6050 ÷ 50 = 1800/121 days

= 14 106/121 days or 14.876

Thus, Emily, Michelle, and Carol together will finish the work in 14 106/121 days or 14.876 days Answer


Similar Questions

(1) If Charles can finish the work in 20 days and Kenneth can finish the same work in 23 days, then in how many days both can finish the work together?

(2) If Andrew can finish the work in 38 days and Scott can finish the same work in 41 days, then in how many days both can finish the work together?

(3) Andrew can finish a work in 41 days. Kenneth can finish the same work in 46 days while Kevin can finish the work in 51 days. How long will it take to finish it if they work together?

(4) 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?

(5) Alexander can finish a work in 91 days. Patrick can finish the same work in 96 days while Raymond can finish the work in 101 days. How long will it take to finish it if they work together?

(6) 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?

(7) Eric can finish a work in 71 days. Stephen can finish the same work in 76 days while Larry can finish the work in 81 days. How long will it take to finish it if they work together?

(8) Dorothy can finish a work in 46 days. Melissa can finish the same work in 47 days while Deborah can finish the work in 48 days. How long will it take to finish it if they work together?

(9) If David can finish the work in 10 days and Christopher can finish the same work in 14 days, then in how many days both can finish the work together?

(10) Carol can finish a work in 46 days. Dorothy can finish the same work in 51 days while Melissa can finish the work in 56 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. ©