Time and Work
MCQs Math


Question:     If Janet can finish the work in 98 days and Russell can finish the same work in 103 days, then in how many days both can finish the work together?


Correct Answer  50 44/201 days or 50.219 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Janet = 98 days

And, the number of days to finish the same work by Russell = 103 days

Thus, the number of days to finish the work by Janet and Russell together = ?

Here,

∵ In 98 days the work done by Janet = 1

∴ In 1 day, the work done by Janet = 1/98 part

Similarly,

∵ In 103 days the work done by Russell = 1

∴ In 1 day, the work done by Russell = 1/103 part

Now, in 1 day, the work done by Janet and Russell together

= In 1 day work done by Janet + In 1 day the work done by Russell

= 1/98 + 1/103

= 103 + 98/10094

= 201/10094 part of work

This means in 1 day, 201/10094 part of work is done by Janet and Russell working together.

Now, the number of days required to finish 201/10094 part of work by Janet + Russell working together = 1

∴ the number of days required to finish 1 work by Janet + Russell together

= 1/201/10094

= 1 × 10094/201 = 10094/201 days

= 50 44/201 days = or 50.219 days

Thus, Janet and Russell working together will finish the work in 50 44/201 days = or 50.219 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 Janet = 98 days

And the number of days required to finish the same work by Russell = 103 days

Thus, the number of days required to finish the work Janet and Russell working together = ?

Here a = 98 days

And, b = 103 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Janet and Russell working together

= 98 × 103/98 + 103 days

= 10094/201 days

= 50 44/201 days or 50.219

Thus, Janet and Russell together will finish the work in 50 44/201 days or 50.219 days Answer


Similar Questions

(1) If A can do a piece of work in 2 days, B can do the same piece of work in 3 days, while C alone can do the same work in 4 days. Find the number of days to finish the work when they all will work together.

(2) Sandra can finish a work in 34 days. Kimberly can finish the same work in 39 days while Emily can finish the work in 44 days. How long will it take to finish it if they work together?

(3) If Kimberly can finish the work in 35 days and Stephen can finish the same work in 38 days, then in how many days both can finish the work together?

(4) If Linda can finish the work in 31 days and Charles can finish the same work in 47 days, then in how many days both can finish the work together?

(5) If Annie can finish a work in 3 days and Bobby can finish the same work in 6 days, then in how many days they both can finish the work working together?

(6) Joseph can finish a work in 15 days. Thomas can finish the same work in 16 days while Charles can finish the work in 17 days. How long will it take to finish it if they work together?

(7) If Annie can finish a work in 5 days and Bobby can finish the same work in 10 days, then in how many days they both can finish the work working together?

(8) If Melissa can finish the work in 49 days and Jerry can finish the same work in 52 days, then in how many days both can finish the work together?

(9) 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?

(10) If Angela can finish the work in 70 days and Terry can finish the same work in 75 days, then in how many days both can finish the work together?


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