Time and Work
MCQs Math


Question:     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?


Correct Answer  3 15/17 days or 3.882 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Mary = 6 days

And, the number of days to finish the same work by Michael = 11 days

Thus, the number of days to finish the work by Mary and Michael together = ?

Here,

∵ In 6 days the work done by Mary = 1

∴ In 1 day, the work done by Mary = 1/6 part

Similarly,

∵ In 11 days the work done by Michael = 1

∴ In 1 day, the work done by Michael = 1/11 part

Now, in 1 day, the work done by Mary and Michael together

= In 1 day work done by Mary + In 1 day the work done by Michael

= 1/6 + 1/11

= 11 + 6/66

= 17/66 part of work

This means in 1 day, 17/66 part of work is done by Mary and Michael working together.

Now, the number of days required to finish 17/66 part of work by Mary + Michael working together = 1

∴ the number of days required to finish 1 work by Mary + Michael together

= 1/17/66

= 1 × 66/17 = 66/17 days

= 3 15/17 days = or 3.882 days

Thus, Mary and Michael working together will finish the work in 3 15/17 days = or 3.882 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 Mary = 6 days

And the number of days required to finish the same work by Michael = 11 days

Thus, the number of days required to finish the work Mary and Michael working together = ?

Here a = 6 days

And, b = 11 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Mary and Michael working together

= 6 × 11/6 + 11 days

= 66/17 days

= 3 15/17 days or 3.882

Thus, Mary and Michael together will finish the work in 3 15/17 days or 3.882 days Answer


Similar Questions

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(2) If Rachel can finish the work in 94 days and Roy can finish the same work in 99 days, then in how many days both can finish the work together?

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