Time and Work
MCQs Math


Question:     If George can finish the work in 51 days and Dennis can finish the same work in 56 days, then in how many days both can finish the work together?


Correct Answer  26 74/107 days or 26.692 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by George = 51 days

And, the number of days to finish the same work by Dennis = 56 days

Thus, the number of days to finish the work by George and Dennis together = ?

Here,

∵ In 51 days the work done by George = 1

∴ In 1 day, the work done by George = 1/51 part

Similarly,

∵ In 56 days the work done by Dennis = 1

∴ In 1 day, the work done by Dennis = 1/56 part

Now, in 1 day, the work done by George and Dennis together

= In 1 day work done by George + In 1 day the work done by Dennis

= 1/51 + 1/56

= 56 + 51/2856

= 107/2856 part of work

This means in 1 day, 107/2856 part of work is done by George and Dennis working together.

Now, the number of days required to finish 107/2856 part of work by George + Dennis working together = 1

∴ the number of days required to finish 1 work by George + Dennis together

= 1/107/2856

= 1 × 2856/107 = 2856/107 days

= 26 74/107 days = or 26.692 days

Thus, George and Dennis working together will finish the work in 26 74/107 days = or 26.692 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 George = 51 days

And the number of days required to finish the same work by Dennis = 56 days

Thus, the number of days required to finish the work George and Dennis working together = ?

Here a = 51 days

And, b = 56 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when George and Dennis working together

= 51 × 56/51 + 56 days

= 2856/107 days

= 26 74/107 days or 26.692

Thus, George and Dennis together will finish the work in 26 74/107 days or 26.692 days Answer


Similar Questions

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(2) If Matthew can finish the work in 26 days and Edward can finish the same work in 30 days, then in how many days both can finish the work together?

(3) If Paul can finish the work in 36 days and Larry can finish the same work in 39 days, then in how many days both can finish the work together?

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(6) If Matthew can finish the work in 29 days and Edward can finish the same work in 34 days, then in how many days both can finish the work together?

(7) 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?

(8) Michelle can finish a work in 40 days. Carol can finish the same work in 41 days while Amanda can finish the work in 42 days. How long will it take to finish it if they work together?

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(10) If A can finish a work in 10 days and B can finish the same work in 15 days, then in how many days they both can finish the work working together?


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