Time and Work
MCQs Math


Question:     If Donald can finish the work in 32 days and Nicholas can finish the same work in 35 days, then in how many days both can finish the work together?


Correct Answer  16 48/67 days or 16.716 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Donald = 32 days

And, the number of days to finish the same work by Nicholas = 35 days

Thus, the number of days to finish the work by Donald and Nicholas together = ?

Here,

∵ In 32 days the work done by Donald = 1

∴ In 1 day, the work done by Donald = 1/32 part

Similarly,

∵ In 35 days the work done by Nicholas = 1

∴ In 1 day, the work done by Nicholas = 1/35 part

Now, in 1 day, the work done by Donald and Nicholas together

= In 1 day work done by Donald + In 1 day the work done by Nicholas

= 1/32 + 1/35

= 35 + 32/1120

= 67/1120 part of work

This means in 1 day, 67/1120 part of work is done by Donald and Nicholas working together.

Now, the number of days required to finish 67/1120 part of work by Donald + Nicholas working together = 1

∴ the number of days required to finish 1 work by Donald + Nicholas together

= 1/67/1120

= 1 × 1120/67 = 1120/67 days

= 16 48/67 days = or 16.716 days

Thus, Donald and Nicholas working together will finish the work in 16 48/67 days = or 16.716 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 Donald = 32 days

And the number of days required to finish the same work by Nicholas = 35 days

Thus, the number of days required to finish the work Donald and Nicholas working together = ?

Here a = 32 days

And, b = 35 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Donald and Nicholas working together

= 32 × 35/32 + 35 days

= 1120/67 days

= 16 48/67 days or 16.716

Thus, Donald and Nicholas together will finish the work in 16 48/67 days or 16.716 days Answer


Similar Questions

(1) If Jack can finish the work in 20 days and Bill can finish the same work in 30 days, then in how many days they both can finish the work working together?

(2) Samantha can finish a work in 86 days. Christine can finish the same work in 91 days while Debra can finish the work in 96 days. How long will it take to finish it if they work together?

(3) If Patricia can finish the work in 5 days and William can finish the same work in 8 days, then in how many days both can finish the work together?

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(6) If Kevin can finish the work in 47 days and Frank can finish the same work in 52 days, then in how many days both can finish the work together?

(7) Jessica can finish a work in 20 days. Karen can finish the same work in 25 days while Lisa can finish the work in 30 days. How long will it take to finish it if they work together?

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