Time and Work
MCQs Math


Question:     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?


Correct Answer  7 11/30 days or 7.367 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Barbara = 13 days

And, the number of days to finish the same work by Anthony = 17 days

Thus, the number of days to finish the work by Barbara and Anthony together = ?

Here,

∵ In 13 days the work done by Barbara = 1

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

Similarly,

∵ In 17 days the work done by Anthony = 1

∴ In 1 day, the work done by Anthony = 1/17 part

Now, in 1 day, the work done by Barbara and Anthony together

= In 1 day work done by Barbara + In 1 day the work done by Anthony

= 1/13 + 1/17

= 17 + 13/221

= 30/221 part of work

This means in 1 day, 30/221 part of work is done by Barbara and Anthony working together.

Now, the number of days required to finish 30/221 part of work by Barbara + Anthony working together = 1

∴ the number of days required to finish 1 work by Barbara + Anthony together

= 1/30/221

= 1 × 221/30 = 221/30 days

= 7 11/30 days = or 7.367 days

Thus, Barbara and Anthony working together will finish the work in 7 11/30 days = or 7.367 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 Barbara = 13 days

And the number of days required to finish the same work by Anthony = 17 days

Thus, the number of days required to finish the work Barbara and Anthony working together = ?

Here a = 13 days

And, b = 17 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Barbara and Anthony working together

= 13 × 17/13 + 17 days

= 221/30 days

= 7 11/30 days or 7.367

Thus, Barbara and Anthony together will finish the work in 7 11/30 days or 7.367 days Answer


Similar Questions

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(2) Andrew can finish a work in 37 days. Joshua can finish the same work in 38 days while Kenneth can finish the work in 39 days. How long will it take to finish it if they work together?

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(6) If Linda can finish the work in 9 days and Charles can finish the same work in 12 days, then in how many days both can finish the work together?

(7) Jacob can finish a work in 65 days. Nicholas can finish the same work in 70 days while Eric can finish the work in 75 days. How long will it take to finish it if they work together?

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