Time and Work
MCQs Math


Question:     If Mark can finish the work in 33 days and Jacob can finish the same work in 38 days, then in how many days both can finish the work together?


Correct Answer  17 47/71 days or 17.662 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Mark = 33 days

And, the number of days to finish the same work by Jacob = 38 days

Thus, the number of days to finish the work by Mark and Jacob together = ?

Here,

∵ In 33 days the work done by Mark = 1

∴ In 1 day, the work done by Mark = 1/33 part

Similarly,

∵ In 38 days the work done by Jacob = 1

∴ In 1 day, the work done by Jacob = 1/38 part

Now, in 1 day, the work done by Mark and Jacob together

= In 1 day work done by Mark + In 1 day the work done by Jacob

= 1/33 + 1/38

= 38 + 33/1254

= 71/1254 part of work

This means in 1 day, 71/1254 part of work is done by Mark and Jacob working together.

Now, the number of days required to finish 71/1254 part of work by Mark + Jacob working together = 1

∴ the number of days required to finish 1 work by Mark + Jacob together

= 1/71/1254

= 1 × 1254/71 = 1254/71 days

= 17 47/71 days = or 17.662 days

Thus, Mark and Jacob working together will finish the work in 17 47/71 days = or 17.662 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 Mark = 33 days

And the number of days required to finish the same work by Jacob = 38 days

Thus, the number of days required to finish the work Mark and Jacob working together = ?

Here a = 33 days

And, b = 38 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Mark and Jacob working together

= 33 × 38/33 + 38 days

= 1254/71 days

= 17 47/71 days or 17.662

Thus, Mark and Jacob together will finish the work in 17 47/71 days or 17.662 days Answer


Similar Questions

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