Time and Work
MCQs Math


Question:     If Linda can finish the work in 9 days and Charles can finish the same work in 13 days, then in how many days both can finish the work together?


Correct Answer  5 7/22 days or 5.318 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Linda = 9 days

And, the number of days to finish the same work by Charles = 13 days

Thus, the number of days to finish the work by Linda and Charles together = ?

Here,

∵ In 9 days the work done by Linda = 1

∴ In 1 day, the work done by Linda = 1/9 part

Similarly,

∵ In 13 days the work done by Charles = 1

∴ In 1 day, the work done by Charles = 1/13 part

Now, in 1 day, the work done by Linda and Charles together

= In 1 day work done by Linda + In 1 day the work done by Charles

= 1/9 + 1/13

= 13 + 9/117

= 22/117 part of work

This means in 1 day, 22/117 part of work is done by Linda and Charles working together.

Now, the number of days required to finish 22/117 part of work by Linda + Charles working together = 1

∴ the number of days required to finish 1 work by Linda + Charles together

= 1/22/117

= 1 × 117/22 = 117/22 days

= 5 7/22 days = or 5.318 days

Thus, Linda and Charles working together will finish the work in 5 7/22 days = or 5.318 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 Linda = 9 days

And the number of days required to finish the same work by Charles = 13 days

Thus, the number of days required to finish the work Linda and Charles working together = ?

Here a = 9 days

And, b = 13 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Linda and Charles working together

= 9 × 13/9 + 13 days

= 117/22 days

= 5 7/22 days or 5.318

Thus, Linda and Charles together will finish the work in 5 7/22 days or 5.318 days Answer


Similar Questions

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(2) If Stephen can finish the work in 75 days and Carl can finish the same work in 80 days, then in how many days both can finish the work together?

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(6) Michael can finish a work in 11 days. William can finish the same work in 16 days while Richard can finish the work in 21 days. How long will it take to finish it if they work together?

(7) 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?

(8) 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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