Time and Work
MCQs Math


Question:     If Kenneth can finish the work in 45 days and Gregory can finish the same work in 50 days, then in how many days both can finish the work together?


Correct Answer  23 13/19 days or 23.684 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Kenneth = 45 days

And, the number of days to finish the same work by Gregory = 50 days

Thus, the number of days to finish the work by Kenneth and Gregory together = ?

Here,

∵ In 45 days the work done by Kenneth = 1

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

Similarly,

∵ In 50 days the work done by Gregory = 1

∴ In 1 day, the work done by Gregory = 1/50 part

Now, in 1 day, the work done by Kenneth and Gregory together

= In 1 day work done by Kenneth + In 1 day the work done by Gregory

= 1/45 + 1/50

= 10 + 9/450

= 19/450 part of work

This means in 1 day, 19/450 part of work is done by Kenneth and Gregory working together.

Now, the number of days required to finish 19/450 part of work by Kenneth + Gregory working together = 1

∴ the number of days required to finish 1 work by Kenneth + Gregory together

= 1/19/450

= 1 × 450/19 = 450/19 days

= 23 13/19 days = or 23.684 days

Thus, Kenneth and Gregory working together will finish the work in 23 13/19 days = or 23.684 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 Kenneth = 45 days

And the number of days required to finish the same work by Gregory = 50 days

Thus, the number of days required to finish the work Kenneth and Gregory working together = ?

Here a = 45 days

And, b = 50 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Kenneth and Gregory working together

= 45 × 50/45 + 50 days

= 2250/95 days

= 2250 ÷ 5/95 ÷ 5 = 450/19 days

= 23 13/19 days or 23.684

Thus, Kenneth and Gregory together will finish the work in 23 13/19 days or 23.684 days Answer


Similar Questions

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(2) 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?

(3) If Margaret can finish the work in 29 days and Ryan can finish the same work in 32 days, then in how many days both can finish the work together?

(4) Debra can finish a work in 92 days. Carolyn can finish the same work in 97 days while Janet can finish the work in 102 days. How long will it take to finish it if they work together?

(5) If Carol can finish the work in 43 days and Alexander can finish the same work in 46 days, then in how many days both can finish the work together?

(6) If Brian can finish the work in 46 days and Raymond can finish the same work in 50 days, then in how many days both can finish the work together?

(7) Andrew can finish a work in 37 days. Joshua can finish the same work in 38 days while Kenneth can finish the work in 39 days. How long will it take to finish it if they work together?

(8) If Susan can finish the work in 15 days and Donald can finish the same work in 18 days, then in how many days both can finish the work together?

(9) Catherine can finish a work in 100 days. Heather can finish the same work in 105 days while Diane can finish the work in 110 days. How long will it take to finish it if they work together?

(10) 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?


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