Time and Work
MCQs Math


Question:     If Jennifer can finish the work in 29 days and Joseph can finish the same work in 45 days, then in how many days both can finish the work together?


Correct Answer  17 47/74 days or 17.635 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Jennifer = 29 days

And, the number of days to finish the same work by Joseph = 45 days

Thus, the number of days to finish the work by Jennifer and Joseph together = ?

Here,

∵ In 29 days the work done by Jennifer = 1

∴ In 1 day, the work done by Jennifer = 1/29 part

Similarly,

∵ In 45 days the work done by Joseph = 1

∴ In 1 day, the work done by Joseph = 1/45 part

Now, in 1 day, the work done by Jennifer and Joseph together

= In 1 day work done by Jennifer + In 1 day the work done by Joseph

= 1/29 + 1/45

= 45 + 29/1305

= 74/1305 part of work

This means in 1 day, 74/1305 part of work is done by Jennifer and Joseph working together.

Now, the number of days required to finish 74/1305 part of work by Jennifer + Joseph working together = 1

∴ the number of days required to finish 1 work by Jennifer + Joseph together

= 1/74/1305

= 1 × 1305/74 = 1305/74 days

= 17 47/74 days = or 17.635 days

Thus, Jennifer and Joseph working together will finish the work in 17 47/74 days = or 17.635 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 Jennifer = 29 days

And the number of days required to finish the same work by Joseph = 45 days

Thus, the number of days required to finish the work Jennifer and Joseph working together = ?

Here a = 29 days

And, b = 45 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Jennifer and Joseph working together

= 29 × 45/29 + 45 days

= 1305/74 days

= 17 47/74 days or 17.635

Thus, Jennifer and Joseph together will finish the work in 17 47/74 days or 17.635 days Answer


Similar Questions

(1) If Lisa can finish the work in 23 days and George can finish the same work in 26 days, then in how many days both can finish the work together?

(2) If Karen can finish the work in 21 days and Kevin can finish the same work in 25 days, then in how many days both can finish the work together?

(3) If James can finish the work in 2 days and John can finish the same work in 5 days, then in how many days both can finish the work together?

(4) If Jonathan can finish the work in 73 days and Sean can finish the same work in 78 days, then in how many days both can finish the work together?

(5) If Richard can finish the work in 17 days and Mark can finish the same work in 22 days, then in how many days both can finish the work together?

(6) Samuel can finish a work in 87 days. Alexander can finish the same work in 92 days while Frank can finish the work in 97 days. How long will it take to finish it if they work together?

(7) Karen can finish a work in 24 days. Nancy can finish the same work in 29 days while Betty can finish the work in 34 days. How long will it take to finish it if they work together?

(8) If Jack can finish a work in 8 days and Bill can finish the same work in 12 days, then in how many days they both can finish the work working together?

(9) Betty can finish a work in 26 days. Margaret can finish the same work in 27 days while Sandra can finish the work in 28 days. How long will it take to finish it if they work together?

(10) Susan can finish a work in 18 days. Sarah can finish the same work in 23 days while Karen can finish the work in 28 days. How long will it take to finish it if they work together?


NCERT Solution and CBSE Notes for class twelve, eleventh, tenth, ninth, seventh, sixth, fifth, fourth and General Math for competitive Exams. ©