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) If Joseph can finish the work in 19 days and Steven can finish the same work in 24 days, then in how many days both can finish the work together?

(2) If Angela can finish the work in 70 days and Terry can finish the same work in 75 days, then in how many days both can finish the work together?

(3) If Richard can finish the work in 14 days and Mark can finish the same work in 17 days, then in how many days both can finish the work together?

(4) If A can do a piece of work in 2 days, B can do the same piece of work in 3 days, while C alone can do the same work in 4 days. Find the number of days to finish the work when they all will work together.

(5) Helen can finish a work in 84 days. Katherine can finish the same work in 89 days while Christine can finish the work in 94 days. How long will it take to finish it if they work together?

(6) 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?

(7) If Rebecca can finish the work in 58 days and Henry can finish the same work in 63 days, then in how many days both can finish the work together?

(8) If Margaret can finish the work in 29 days and Ryan can finish the same work in 32 days, then in how many days both can finish the work together?

(9) If Matthew can finish the work in 26 days and Edward can finish the same work in 29 days, then in how many days both can finish the work together?

(10) Patricia can finish a work in 4 days. Jennifer can finish the same work in 5 days while Linda can finish the work in 6 days. How long will it take to finish it if they work together?


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