Time and Work
MCQs Math


Question:     If Michelle can finish the work in 41 days and Samuel can finish the same work in 45 days, then in how many days both can finish the work together?


Correct Answer  21 39/86 days or 21.453 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Michelle = 41 days

And, the number of days to finish the same work by Samuel = 45 days

Thus, the number of days to finish the work by Michelle and Samuel together = ?

Here,

∵ In 41 days the work done by Michelle = 1

∴ In 1 day, the work done by Michelle = 1/41 part

Similarly,

∵ In 45 days the work done by Samuel = 1

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

Now, in 1 day, the work done by Michelle and Samuel together

= In 1 day work done by Michelle + In 1 day the work done by Samuel

= 1/41 + 1/45

= 45 + 41/1845

= 86/1845 part of work

This means in 1 day, 86/1845 part of work is done by Michelle and Samuel working together.

Now, the number of days required to finish 86/1845 part of work by Michelle + Samuel working together = 1

∴ the number of days required to finish 1 work by Michelle + Samuel together

= 1/86/1845

= 1 × 1845/86 = 1845/86 days

= 21 39/86 days = or 21.453 days

Thus, Michelle and Samuel working together will finish the work in 21 39/86 days = or 21.453 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 Michelle = 41 days

And the number of days required to finish the same work by Samuel = 45 days

Thus, the number of days required to finish the work Michelle and Samuel working together = ?

Here a = 41 days

And, b = 45 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Michelle and Samuel working together

= 41 × 45/41 + 45 days

= 1845/86 days

= 21 39/86 days or 21.453

Thus, Michelle and Samuel together will finish the work in 21 39/86 days or 21.453 days Answer


Similar Questions

(1) Debra can finish a work in 92 days. Carolyn can finish the same work in 97 days while Janet can finish the work in 102 days. How long will it take to finish it if they work together?

(2) If Kenneth can finish the work in 42 days and Gregory can finish the same work in 45 days, then in how many days both can finish the work together?

(3) Jennifer can finish a work in 6 days. Linda can finish the same work in 7 days while Elizabeth can finish the work in 8 days. How long will it take to finish it if they work together?

(4) Kimberly can finish a work in 38 days. Donna can finish the same work in 43 days while Michelle can finish the work in 48 days. How long will it take to finish it if they work together?

(5) Nancy can finish a work in 28 days. Margaret can finish the same work in 33 days while Sandra can finish the work in 38 days. How long will it take to finish it if they work together?

(6) 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?

(7) If Gregory can finish the work in 89 days and Alan can finish the same work in 94 days, then in how many days both can finish the work together?

(8) Joseph can finish a work in 19 days. Charles can finish the same work in 24 days while Christopher can finish the work in 29 days. How long will it take to finish it if they work together?

(9) If Joseph can finish the work in 19 days and Steven can finish the same work in 24 days, then in how many days both can finish the work together?

(10) If Helen can finish the work in 84 days and Bruce can finish the same work in 89 days, then in how many days both can finish the work together?


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