Time and Work
MCQs Math


Question:     If John can finish the work in 9 days and Richard can finish the same work in 14 days, then in how many days both can finish the work together?


Correct Answer  5 11/23 days or 5.478 days

Solution And Explanation

Solution

Given,

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

And, the number of days to finish the same work by Richard = 14 days

Thus, the number of days to finish the work by John and Richard together = ?

Here,

∵ In 9 days the work done by John = 1

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

Similarly,

∵ In 14 days the work done by Richard = 1

∴ In 1 day, the work done by Richard = 1/14 part

Now, in 1 day, the work done by John and Richard together

= In 1 day work done by John + In 1 day the work done by Richard

= 1/9 + 1/14

= 14 + 9/126

= 23/126 part of work

This means in 1 day, 23/126 part of work is done by John and Richard working together.

Now, the number of days required to finish 23/126 part of work by John + Richard working together = 1

∴ the number of days required to finish 1 work by John + Richard together

= 1/23/126

= 1 × 126/23 = 126/23 days

= 5 11/23 days = or 5.478 days

Thus, John and Richard working together will finish the work in 5 11/23 days = or 5.478 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 John = 9 days

And the number of days required to finish the same work by Richard = 14 days

Thus, the number of days required to finish the work John and Richard working together = ?

Here a = 9 days

And, b = 14 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when John and Richard working together

= 9 × 14/9 + 14 days

= 126/23 days

= 5 11/23 days or 5.478

Thus, John and Richard together will finish the work in 5 11/23 days or 5.478 days Answer


Similar Questions

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(2) If Daniel can finish the work in 24 days and Timothy can finish the same work in 27 days, then in how many days both can finish the work together?

(3) If Kenneth can finish the work in 42 days and Gregory can finish the same work in 46 days, then in how many days both can finish the work together?

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(6) 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?

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