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 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?

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