Time and Work
MCQs Math


Question:     If Christopher can finish the work in 22 days and Brian can finish the same work in 26 days, then in how many days both can finish the work together?


Correct Answer  11 11/12 days or 11.917 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Christopher = 22 days

And, the number of days to finish the same work by Brian = 26 days

Thus, the number of days to finish the work by Christopher and Brian together = ?

Here,

∵ In 22 days the work done by Christopher = 1

∴ In 1 day, the work done by Christopher = 1/22 part

Similarly,

∵ In 26 days the work done by Brian = 1

∴ In 1 day, the work done by Brian = 1/26 part

Now, in 1 day, the work done by Christopher and Brian together

= In 1 day work done by Christopher + In 1 day the work done by Brian

= 1/22 + 1/26

= 13 + 11/286

= 24/286 part of work

= 24 ÷ 2/286 ÷ 2 part of work

= 12/143 part of work

This means, in 1 day, 12/143 part of the work is done by Christopher and Brian together.

Now, the number of days required to finish 12/143 part of work by Christopher + Brian working together = 1

∴ the number of days required to finish 1 work by Christopher + Brian together

= 1/12/143

= 1 × 143/12 = 143/12 days

= 11 11/12 days = or 11.917 days

Thus, Christopher and Brian working together will finish the work in 11 11/12 days = or 11.917 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, and B can finish the same work in b days,
then working together the number of days require to finish the work
= a × b/a + b days.

Here given,

The number of days required to finish the work by Christopher = 22 days

And the number of days required to finish the same work by Brian = 26 days

Thus, the number of days required to finish the work Christopher and Brian working together = ?

Here a = 22 days

And, b = 26 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Christopher and Brian working together

= 22 × 26/22 + 26 days

= 572/48 days

= 572 ÷ 4/48 ÷ 4 = 143/12 days

= 11 11/12 days or 11.917

Thus, Christopher and Brian together will finish the work in 11 11/12 days or 11.917 days Answer


Similar Questions

(1) Daniel can finish a work in 27 days. Anthony can finish the same work in 32 days while Mark can finish the work in 37 days. How long will it take to finish it if they work together?

(2) Nicole can finish a work in 82 days. Samantha can finish the same work in 87 days while Katherine can finish the work in 92 days. How long will it take to finish it if they work together?

(3) Anthony can finish a work in 27 days. Mark can finish the same work in 28 days while Donald can finish the work in 29 days. How long will it take to finish it if they work together?

(4) Kimberly can finish a work in 38 days. Donna can finish the same work in 43 days while Michelle can finish the work in 48 days. How long will it take to finish it if they work together?

(5) If David can finish the work in 13 days and Christopher can finish the same work in 18 days, then in how many days both can finish the work together?

(6) Sarah can finish a work in 22 days. Lisa can finish the same work in 27 days while Nancy can finish the work in 32 days. How long will it take to finish it if they work together?

(7) John can finish a work in 5 days. Michael can finish the same work in 6 days while David can finish the work in 7 days. How long will it take to finish it if they work together?

(8) If Michael can finish the work in 11 days and Thomas can finish the same work in 16 days, then in how many days both can finish the work together?

(9) Melissa can finish a work in 52 days. Stephanie can finish the same work in 57 days while Rebecca can finish the work in 62 days. How long will it take to finish it if they work together?

(10) If George can finish the work in 48 days and Dennis can finish the same work in 51 days, then in how many days both can finish the work together?


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