Time and Work
MCQs Math


Question:     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?


Correct Answer  22 41/90 days or 22.456 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Carol = 43 days

And, the number of days to finish the same work by Alexander = 47 days

Thus, the number of days to finish the work by Carol and Alexander together = ?

Here,

∵ In 43 days the work done by Carol = 1

∴ In 1 day, the work done by Carol = 1/43 part

Similarly,

∵ In 47 days the work done by Alexander = 1

∴ In 1 day, the work done by Alexander = 1/47 part

Now, in 1 day, the work done by Carol and Alexander together

= In 1 day work done by Carol + In 1 day the work done by Alexander

= 1/43 + 1/47

= 47 + 43/2021

= 90/2021 part of work

This means in 1 day, 90/2021 part of work is done by Carol and Alexander working together.

Now, the number of days required to finish 90/2021 part of work by Carol + Alexander working together = 1

∴ the number of days required to finish 1 work by Carol + Alexander together

= 1/90/2021

= 1 × 2021/90 = 2021/90 days

= 22 41/90 days = or 22.456 days

Thus, Carol and Alexander working together will finish the work in 22 41/90 days = or 22.456 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 Carol = 43 days

And the number of days required to finish the same work by Alexander = 47 days

Thus, the number of days required to finish the work Carol and Alexander working together = ?

Here a = 43 days

And, b = 47 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Carol and Alexander working together

= 43 × 47/43 + 47 days

= 2021/90 days

= 22 41/90 days or 22.456

Thus, Carol and Alexander together will finish the work in 22 41/90 days or 22.456 days Answer


Similar Questions

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(2) If Thomas can finish the work in 21 days and Andrew can finish the same work in 26 days, then in how many days both can finish the work together?

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