Time and Work
MCQs Math


Question:     If Joshua can finish the work in 40 days and Benjamin can finish the same work in 44 days, then in how many days both can finish the work together?


Correct Answer  20 20/21 days or 20.952 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 = 44 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 44 days the work done by Benjamin = 1

∴ In 1 day, the work done by Benjamin = 1/44 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 + 1/44

= 11 + 10/440

= 21/440 part of work

This means in 1 day, 21/440 part of work is done by Joshua and Benjamin working together.

Now, the number of days required to finish 21/440 part of work by Joshua + Benjamin working together = 1

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

= 1/21/440

= 1 × 440/21 = 440/21 days

= 20 20/21 days = or 20.952 days

Thus, Joshua and Benjamin working together will finish the work in 20 20/21 days = or 20.952 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 = 44 days

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

Here a = 40 days

And, b = 44 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 × 44/40 + 44 days

= 1760/84 days

= 1760 ÷ 4/84 ÷ 4 = 440/21 days

= 20 20/21 days or 20.952

Thus, Joshua and Benjamin together will finish the work in 20 20/21 days or 20.952 days Answer


Similar Questions

(1) If Susan can finish the work in 18 days and Donald can finish the same work in 23 days, then in how many days both can finish the work together?

(2) If Sarah can finish the work in 19 days and Joshua can finish the same work in 23 days, then in how many days both can finish the work together?

(3) Justin can finish a work in 79 days. Brandon can finish the same work in 84 days while Benjamin can finish the work in 89 days. How long will it take to finish it if they work together?

(4) If Richard can finish the work in 14 days and Mark can finish the same work in 18 days, then in how many days both can finish the work together?

(5) If Sharon can finish the work in 60 days and Zachary can finish the same work in 65 days, then in how many days both can finish the work together?

(6) Christine can finish a work in 90 days. Rachel can finish the same work in 95 days while Carolyn can finish the work in 100 days. How long will it take to finish it if they work together?

(7) If A can finish a work in 10 days and B can finish the same work in 15 days, then in how many days they both can finish the work working together?

(8) If Elizabeth can finish the work in 11 days and Daniel can finish the same work in 15 days, then in how many days both can finish the work together?

(9) Nicole can finish a work in 82 days. Samantha can finish the same work in 87 days while Katherine can finish the work in 92 days. How long will it take to finish it if they work together?

(10) Stephanie can finish a work in 56 days. Sharon can finish the same work in 61 days while Laura can finish the work in 66 days. How long will it take to finish it if they work together?


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