Time and Work
MCQs Math


Question:     Amanda can finish a work in 48 days. Melissa can finish the same work in 53 days while Deborah can finish the work in 58 days. How long will it take to finish it if they work together?


Correct Answer  17 2359/4201 days or 17.562 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Amanda = 48 days

And, the number of days required to finish the same work by Melissa = 53 days

And, the number of days required to finish the same work by Deborah = 58 days

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

Here,

∵ In 48 days the work is done by Amanda = 1

∴ The work done by Amanda in 1 day = 1/48

Similarly,

∵ In 53 days the work is done by Melissa = 1

∴ The work done by Melissa in 1 day = 1/53

Similarly,

∵ In 58 days the work is done by Deborah = 1

∴ The work done by Deborah in 1 day = 1/58 part

Now, the work done by Amanda, Melissa, and Deborah together in 1 day

= Amanda's 1 day work + Melissa's 1 day work + Deborah's 1 day work

= 1/48 + 1/53 + 1/58

= 1537 + 1392 + 1272/73776

= 4201/73776 part of work

This means in 1 day, 4201/73776 part of work is done by Amanda, Melissa and Deborah working together.

Now, the number of days required to finish 4201/73776 part of work by Amanda, Melissa, and Deborah working together = 1

∴ the number of days required to finish the whole work (1 work) by Amanda + Melissa + Deborah together

= 1/4201/73776

= 1 × 73776/4201 = 73776/4201 days

= 17 2359/4201 days = or 17.562 days

Thus, Amanda, Melissa, and Deborah working together will finish the total work (1 work) in 17 2359/4201 days = or 17.562 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 Amanda = 48 days

And the number of days required to finish the same work by Melissa = 53 days

And the number of days required to finish the work by Deborah = 58 days

Thus, the number of days required to finish the work by Amanda, Melissa, and Deborah together = ?

Here a = 48 days

And, b = 53 days

And, c = 58 days

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

The number of days required to finish the work when Amanda, Melissa, and Deborah working together

= 48 × 53 × 58/48 × 53 + 48 × 58 + 53 × 58 days

= 147552/2544 + 2784 + 3074 days

= 147552/8402 days

= 147552/8402 days

= 147552 ÷ 2/8402 ÷ 2 = 73776/4201 days

= 17 2359/4201 days or 17.562

Thus, Amanda, Melissa, and Deborah together will finish the work in 17 2359/4201 days or 17.562 days Answer


Similar Questions

(1) If Paul can finish the work in 36 days and Larry can finish the same work in 40 days, then in how many days both can finish the work together?

(2) If Susan can finish the work in 15 days and Donald can finish the same work in 18 days, then in how many days both can finish the work together?

(3) Charles can finish a work in 19 days. Christopher can finish the same work in 20 days while Daniel can finish the work in 21 days. How long will it take to finish it if they work together?

(4) If Annie can finish a work in 5 days and Bobby can finish the same work in 10 days, then in how many days they both can finish the work working together?

(5) If Joshua can finish the work in 40 days and Benjamin can finish the same work in 44 days, then in how many days both can finish the work together?

(6) If John can finish the work in 9 days and Richard can finish the same work in 14 days, then in how many days both can finish the work together?

(7) Andrew can finish a work in 37 days. Joshua can finish the same work in 38 days while Kenneth can finish the work in 39 days. How long will it take to finish it if they work together?

(8) If Shirley can finish the work in 72 days and Harold can finish the same work in 77 days, then in how many days both can finish the work together?

(9) If William can finish the work in 12 days and Matthew can finish the same work in 16 days, then in how many days both can finish the work together?

(10) William can finish a work in 11 days. Richard can finish the same work in 12 days while Joseph can finish the work in 13 days. How long will it take to finish it if they work together?


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