Time and Work
MCQs Math


Question:     If Joshua can finish the work in 40 days and Benjamin can finish the same work in 43 days, then in how many days both can finish the work together?


Correct Answer  20 60/83 days or 20.723 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Joshua = 40 days

And, the number of days to finish the same work by Benjamin = 43 days

Thus, the number of days to finish the work by Joshua and Benjamin together = ?

Here,

∵ In 40 days the work done by Joshua = 1

∴ In 1 day, the work done by Joshua = 1/40 part

Similarly,

∵ In 43 days the work done by Benjamin = 1

∴ In 1 day, the work done by Benjamin = 1/43 part

Now, in 1 day, the work done by Joshua and Benjamin together

= In 1 day work done by Joshua + In 1 day the work done by Benjamin

= 1/40 + 1/43

= 43 + 40/1720

= 83/1720 part of work

This means in 1 day, 83/1720 part of work is done by Joshua and Benjamin working together.

Now, the number of days required to finish 83/1720 part of work by Joshua + Benjamin working together = 1

∴ the number of days required to finish 1 work by Joshua + Benjamin together

= 1/83/1720

= 1 × 1720/83 = 1720/83 days

= 20 60/83 days = or 20.723 days

Thus, Joshua and Benjamin working together will finish the work in 20 60/83 days = or 20.723 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 Joshua = 40 days

And the number of days required to finish the same work by Benjamin = 43 days

Thus, the number of days required to finish the work Joshua and Benjamin working together = ?

Here a = 40 days

And, b = 43 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Joshua and Benjamin working together

= 40 × 43/40 + 43 days

= 1720/83 days

= 20 60/83 days or 20.723

Thus, Joshua and Benjamin together will finish the work in 20 60/83 days or 20.723 days Answer


Similar Questions

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(2) Gregory can finish a work in 89 days. Frank can finish the same work in 94 days while Patrick can finish the work in 99 days. How long will it take to finish it if they work together?

(3) 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?

(4) Anthony can finish a work in 31 days. Donald can finish the same work in 36 days while Steven can finish the work in 41 days. How long will it take to finish it if they work together?

(5) Kimberly can finish a work in 34 days. Emily can finish the same work in 35 days while Donna can finish the work in 36 days. How long will it take to finish it if they work together?

(6) If Gary can finish the work in 67 days and Christian can finish the same work in 72 days, then in how many days both can finish the work together?

(7) If Shirley can finish the work in 72 days and Harold can finish the same work in 77 days, then in how many days both can finish the work together?

(8) Christopher can finish a work in 21 days. Daniel can finish the same work in 22 days while Matthew can finish the work in 23 days. How long will it take to finish it if they work together?

(9) If Ashley can finish the work in 36 days and Eric can finish the same work in 41 days, then in how many days both can finish the work together?

(10) If Mark can finish the work in 30 days and Jacob can finish the same work in 33 days, then in how many days both can finish the work together?


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