Time and Work
MCQs Math


Question:     If William can finish the work in 34 days and Matthew can finish the same work in 50 days, then in how many days both can finish the work together?


Correct Answer  20 5/21 days or 20.238 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by William = 34 days

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

Thus, the number of days to finish the work by William and Matthew together = ?

Here,

∵ In 34 days the work done by William = 1

∴ In 1 day, the work done by William = 1/34 part

Similarly,

∵ In 50 days the work done by Matthew = 1

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

Now, in 1 day, the work done by William and Matthew together

= In 1 day work done by William + In 1 day the work done by Matthew

= 1/34 + 1/50

= 25 + 17/850

= 42/850 part of work

= 42 ÷ 2/850 ÷ 2 part of work

= 21/425 part of work

This means, in 1 day, 21/425 part of the work is done by William and Matthew together.

Now, the number of days required to finish 21/425 part of work by William + Matthew working together = 1

∴ the number of days required to finish 1 work by William + Matthew together

= 1/21/425

= 1 × 425/21 = 425/21 days

= 20 5/21 days = or 20.238 days

Thus, William and Matthew working together will finish the work in 20 5/21 days = or 20.238 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 William = 34 days

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

Thus, the number of days required to finish the work William and Matthew working together = ?

Here a = 34 days

And, b = 50 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when William and Matthew working together

= 34 × 50/34 + 50 days

= 1700/84 days

= 1700 ÷ 4/84 ÷ 4 = 425/21 days

= 20 5/21 days or 20.238

Thus, William and Matthew together will finish the work in 20 5/21 days or 20.238 days Answer


Similar Questions

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(2) Frank can finish a work in 93 days. Raymond can finish the same work in 98 days while Jack can finish the work in 103 days. How long will it take to finish it if they work together?

(3) If Nancy can finish the work in 25 days and Ronald can finish the same work in 28 days, then in how many days both can finish the work together?

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(6) Robert can finish a work in 3 days. John can finish the same work in 4 days while Michael can finish the work in 5 days. How long will it take to finish it if they work together?

(7) If Jennifer can finish the work in 7 days and Joseph can finish the same work in 10 days, then in how many days both can finish the work together?

(8) 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?

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(10) If Charles can finish the work in 23 days and Kenneth can finish the same work in 28 days, then in how many days both can finish the work together?


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