Time and Work
MCQs Math


Question:     If Lisa can finish the work in 26 days and George can finish the same work in 31 days, then in how many days both can finish the work together?


Correct Answer  14 8/57 days or 14.14 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Lisa = 26 days

And, the number of days to finish the same work by George = 31 days

Thus, the number of days to finish the work by Lisa and George together = ?

Here,

∵ In 26 days the work done by Lisa = 1

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

Similarly,

∵ In 31 days the work done by George = 1

∴ In 1 day, the work done by George = 1/31 part

Now, in 1 day, the work done by Lisa and George together

= In 1 day work done by Lisa + In 1 day the work done by George

= 1/26 + 1/31

= 31 + 26/806

= 57/806 part of work

This means in 1 day, 57/806 part of work is done by Lisa and George working together.

Now, the number of days required to finish 57/806 part of work by Lisa + George working together = 1

∴ the number of days required to finish 1 work by Lisa + George together

= 1/57/806

= 1 × 806/57 = 806/57 days

= 14 8/57 days = or 14.14 days

Thus, Lisa and George working together will finish the work in 14 8/57 days = or 14.14 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 Lisa = 26 days

And the number of days required to finish the same work by George = 31 days

Thus, the number of days required to finish the work Lisa and George working together = ?

Here a = 26 days

And, b = 31 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Lisa and George working together

= 26 × 31/26 + 31 days

= 806/57 days

= 14 8/57 days or 14.14

Thus, Lisa and George together will finish the work in 14 8/57 days or 14.14 days Answer


Similar Questions

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(2) If Anna can finish the work in 74 days and Austin can finish the same work in 79 days, then in how many days both can finish the work together?

(3) Ashley can finish a work in 36 days. Emily can finish the same work in 41 days while Donna can finish the work in 46 days. How long will it take to finish it if they work together?

(4) If Sandra can finish the work in 34 days and Gary can finish the same work in 39 days, then in how many days both can finish the work together?

(5) If Betty can finish the work in 27 days and Jason can finish the same work in 31 days, then in how many days both can finish the work together?

(6) If Charles can finish the work in 23 days and Kenneth can finish the same work in 28 days, then in how many days both can finish the work together?

(7) If Barbara can finish the work in 13 days and Anthony can finish the same work in 17 days, then in how many days both can finish the work together?

(8) Deborah can finish a work in 50 days. Stephanie can finish the same work in 51 days while Rebecca can finish the work in 52 days. How long will it take to finish it if they work together?

(9) If Barbara can finish the work in 35 days and Anthony can finish the same work in 51 days, then in how many days both can finish the work together?

(10) Mary can finish a work in 6 days. Jennifer can finish the same work in 11 days while Linda can finish the work in 16 days. How long will it take to finish it if they work together?


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