Time and Work
MCQs Math


Question:     Debra can finish a work in 92 days. Carolyn can finish the same work in 97 days while Janet can finish the work in 102 days. How long will it take to finish it if they work together?


Correct Answer  32 3892/14101 days or 32.276 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Debra = 92 days

And, the number of days required to finish the same work by Carolyn = 97 days

And, the number of days required to finish the same work by Janet = 102 days

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

Here,

∵ In 92 days the work is done by Debra = 1

∴ The work done by Debra in 1 day = 1/92

Similarly,

∵ In 97 days the work is done by Carolyn = 1

∴ The work done by Carolyn in 1 day = 1/97

Similarly,

∵ In 102 days the work is done by Janet = 1

∴ The work done by Janet in 1 day = 1/102 part

Now, the work done by Debra, Carolyn, and Janet together in 1 day

= Debra's 1 day work + Carolyn's 1 day work + Janet's 1 day work

= 1/92 + 1/97 + 1/102

= 4947 + 4692 + 4462/455124

= 14101/455124 part of work

This means in 1 day, 14101/455124 part of work is done by Debra, Carolyn and Janet working together.

Now, the number of days required to finish 14101/455124 part of work by Debra, Carolyn, and Janet working together = 1

∴ the number of days required to finish the whole work (1 work) by Debra + Carolyn + Janet together

= 1/14101/455124

= 1 × 455124/14101 = 455124/14101 days

= 32 3892/14101 days = or 32.276 days

Thus, Debra, Carolyn, and Janet working together will finish the total work (1 work) in 32 3892/14101 days = or 32.276 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 Debra = 92 days

And the number of days required to finish the same work by Carolyn = 97 days

And the number of days required to finish the work by Janet = 102 days

Thus, the number of days required to finish the work by Debra, Carolyn, and Janet together = ?

Here a = 92 days

And, b = 97 days

And, c = 102 days

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

The number of days required to finish the work when Debra, Carolyn, and Janet working together

= 92 × 97 × 102/92 × 97 + 92 × 102 + 97 × 102 days

= 910248/8924 + 9384 + 9894 days

= 910248/28202 days

= 910248/28202 days

= 910248 ÷ 2/28202 ÷ 2 = 455124/14101 days

= 32 3892/14101 days or 32.276

Thus, Debra, Carolyn, and Janet together will finish the work in 32 3892/14101 days or 32.276 days Answer


Similar Questions

(1) If Charles can finish the work in 20 days and Kenneth can finish the same work in 24 days, then in how many days both can finish the work together?

(2) If Anthony can finish the work in 28 days and Jeffrey can finish the same work in 31 days, then in how many days both can finish the work together?

(3) 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?

(4) If Amanda can finish the work in 45 days and Patrick can finish the same work in 49 days, then in how many days both can finish the work together?

(5) Richard can finish a work in 17 days. Thomas can finish the same work in 22 days while Charles can finish the work in 27 days. How long will it take to finish it if they work together?

(6) If Nancy can finish the work in 25 days and Ronald can finish the same work in 28 days, then in how many days both can finish the work together?

(7) 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?

(8) Samantha can finish a work in 86 days. Christine can finish the same work in 91 days while Debra can finish the work in 96 days. How long will it take to finish it if they work together?

(9) 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?

(10) If Emily can finish the work in 37 days and Justin can finish the same work in 41 days, then in how many days both can finish the work together?


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