Time and Work
MCQs Math


Question:     If Amanda can finish the work in 45 days and Patrick can finish the same work in 48 days, then in how many days both can finish the work together?


Correct Answer  23 7/31 days or 23.226 days

Solution And Explanation

Solution

Given,

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

And, the number of days to finish the same work by Patrick = 48 days

Thus, the number of days to finish the work by Amanda and Patrick together = ?

Here,

∵ In 45 days the work done by Amanda = 1

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

Similarly,

∵ In 48 days the work done by Patrick = 1

∴ In 1 day, the work done by Patrick = 1/48 part

Now, in 1 day, the work done by Amanda and Patrick together

= In 1 day work done by Amanda + In 1 day the work done by Patrick

= 1/45 + 1/48

= 16 + 15/720

= 31/720 part of work

This means in 1 day, 31/720 part of work is done by Amanda and Patrick working together.

Now, the number of days required to finish 31/720 part of work by Amanda + Patrick working together = 1

∴ the number of days required to finish 1 work by Amanda + Patrick together

= 1/31/720

= 1 × 720/31 = 720/31 days

= 23 7/31 days = or 23.226 days

Thus, Amanda and Patrick working together will finish the work in 23 7/31 days = or 23.226 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 Amanda = 45 days

And the number of days required to finish the same work by Patrick = 48 days

Thus, the number of days required to finish the work Amanda and Patrick working together = ?

Here a = 45 days

And, b = 48 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Amanda and Patrick working together

= 45 × 48/45 + 48 days

= 2160/93 days

= 2160 ÷ 3/93 ÷ 3 = 720/31 days

= 23 7/31 days or 23.226

Thus, Amanda and Patrick together will finish the work in 23 7/31 days or 23.226 days Answer


Similar Questions

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(2) If Mary can finish the work in 6 days and Michael can finish the same work in 11 days, then in how many days both can finish the work together?

(3) Sarah can finish a work in 18 days. Karen can finish the same work in 19 days while Lisa can finish the work in 20 days. How long will it take to finish it if they work together?

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(6) If Nicole can finish the work in 82 days and Billy can finish the same work in 87 days, then in how many days both can finish the work together?

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