Time and Work
MCQs Math


Question:     If Elizabeth can finish the work in 33 days and Daniel can finish the same work in 49 days, then in how many days both can finish the work together?


Correct Answer  19 59/82 days or 19.72 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Elizabeth = 33 days

And, the number of days to finish the same work by Daniel = 49 days

Thus, the number of days to finish the work by Elizabeth and Daniel together = ?

Here,

∵ In 33 days the work done by Elizabeth = 1

∴ In 1 day, the work done by Elizabeth = 1/33 part

Similarly,

∵ In 49 days the work done by Daniel = 1

∴ In 1 day, the work done by Daniel = 1/49 part

Now, in 1 day, the work done by Elizabeth and Daniel together

= In 1 day work done by Elizabeth + In 1 day the work done by Daniel

= 1/33 + 1/49

= 49 + 33/1617

= 82/1617 part of work

This means in 1 day, 82/1617 part of work is done by Elizabeth and Daniel working together.

Now, the number of days required to finish 82/1617 part of work by Elizabeth + Daniel working together = 1

∴ the number of days required to finish 1 work by Elizabeth + Daniel together

= 1/82/1617

= 1 × 1617/82 = 1617/82 days

= 19 59/82 days = or 19.72 days

Thus, Elizabeth and Daniel working together will finish the work in 19 59/82 days = or 19.72 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 Elizabeth = 33 days

And the number of days required to finish the same work by Daniel = 49 days

Thus, the number of days required to finish the work Elizabeth and Daniel working together = ?

Here a = 33 days

And, b = 49 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Elizabeth and Daniel working together

= 33 × 49/33 + 49 days

= 1617/82 days

= 19 59/82 days or 19.72

Thus, Elizabeth and Daniel together will finish the work in 19 59/82 days or 19.72 days Answer


Similar Questions

(1) Amy can finish a work in 68 days. Shirley can finish the same work in 73 days while Anna can finish the work in 78 days. How long will it take to finish it if they work together?

(2) Deborah can finish a work in 50 days. Stephanie can finish the same work in 51 days while Rebecca can finish the work in 52 days. How long will it take to finish it if they work together?

(3) If Annie can finish a work in 6 days and Bobby can finish the same work in 12 days, then in how many days they both can finish the work working together?

(4) Alexander can finish a work in 91 days. Patrick can finish the same work in 96 days while Raymond can finish the work in 101 days. How long will it take to finish it if they work together?

(5) Carol can finish a work in 42 days. Amanda can finish the same work in 43 days while Dorothy can finish the work in 44 days. How long will it take to finish it if they work together?

(6) If Stephanie can finish the work in 56 days and Adam can finish the same work in 61 days, then in how many days both can finish the work together?

(7) Melissa can finish a work in 52 days. Stephanie can finish the same work in 57 days while Rebecca can finish the work in 62 days. How long will it take to finish it if they work together?

(8) 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.

(9) If Carol can finish the work in 43 days and Alexander can finish the same work in 47 days, then in how many days both can finish the work together?

(10) If Michelle can finish the work in 41 days and Samuel can finish the same work in 45 days, then in how many days both can finish the work together?


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