Time and Work
MCQs Math


Question:     If Jack can finish the work in 99 days and Bobby can finish the same work in 104 days, then in how many days both can finish the work together?


Correct Answer  50 146/203 days or 50.719 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Jack = 99 days

And, the number of days to finish the same work by Bobby = 104 days

Thus, the number of days to finish the work by Jack and Bobby together = ?

Here,

∵ In 99 days the work done by Jack = 1

∴ In 1 day, the work done by Jack = 1/99 part

Similarly,

∵ In 104 days the work done by Bobby = 1

∴ In 1 day, the work done by Bobby = 1/104 part

Now, in 1 day, the work done by Jack and Bobby together

= In 1 day work done by Jack + In 1 day the work done by Bobby

= 1/99 + 1/104

= 104 + 99/10296

= 203/10296 part of work

This means in 1 day, 203/10296 part of work is done by Jack and Bobby working together.

Now, the number of days required to finish 203/10296 part of work by Jack + Bobby working together = 1

∴ the number of days required to finish 1 work by Jack + Bobby together

= 1/203/10296

= 1 × 10296/203 = 10296/203 days

= 50 146/203 days = or 50.719 days

Thus, Jack and Bobby working together will finish the work in 50 146/203 days = or 50.719 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 Jack = 99 days

And the number of days required to finish the same work by Bobby = 104 days

Thus, the number of days required to finish the work Jack and Bobby working together = ?

Here a = 99 days

And, b = 104 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Jack and Bobby working together

= 99 × 104/99 + 104 days

= 10296/203 days

= 50 146/203 days or 50.719

Thus, Jack and Bobby together will finish the work in 50 146/203 days or 50.719 days Answer


Similar Questions

(1) If Mary can finish the work in 3 days and Michael can finish the same work in 7 days, then in how many days both can finish the work together?

(2) Ryan can finish a work in 63 days. Gary can finish the same work in 68 days while Nicholas can finish the work in 73 days. How long will it take to finish it if they work together?

(3) Kevin can finish a work in 47 days. George can finish the same work in 52 days while Timothy can finish the work in 57 days. How long will it take to finish it if they work together?

(4) If Sandra can finish the work in 31 days and Gary can finish the same work in 35 days, then in how many days both can finish the work together?

(5) If Thomas can finish the work in 21 days and Andrew can finish the same work in 26 days, then in how many days both can finish the work together?

(6) Andrew can finish a work in 41 days. Kenneth can finish the same work in 46 days while Kevin can finish the work in 51 days. How long will it take to finish it if they work together?

(7) If Robert can finish the work in 26 days and David can finish the same work in 42 days, then in how many days both can finish the work together?

(8) Anna can finish a work in 74 days. Pamela can finish the same work in 79 days while Emma can finish the work in 84 days. How long will it take to finish it if they work together?

(9) 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?

(10) Linda can finish a work in 12 days. Barbara can finish the same work in 17 days while Susan can finish the work in 22 days. How long will it take to finish it if they work together?


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