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) If Barbara can finish the work in 13 days and Anthony can finish the same work in 16 days, then in how many days both can finish the work together?

(3) If Thomas can finish the work in 18 days and Andrew can finish the same work in 21 days, then in how many days both can finish the work together?

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(6) If David can finish the work in 32 days and Christopher can finish the same work in 48 days, then in how many days both can finish the work together?

(7) If Elizabeth can finish the work in 14 days and Daniel can finish the same work in 19 days, then in how many days both can finish the work together?

(8) Jack can finish a work in 99 days. Jerry can finish the same work in 104 days while Tyler can finish the work in 109 days. How long will it take to finish it if they work together?

(9) If Robert can finish a work in 4 days and Bob can finish the same work in 6 days, then in how many days they both can finish the work working together?

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