Time and Work
MCQs Math


Question:     If Amy can finish the work in 68 days and Keith can finish the same work in 73 days, then in how many days both can finish the work together?


Correct Answer  35 29/141 days or 35.206 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Amy = 68 days

And, the number of days to finish the same work by Keith = 73 days

Thus, the number of days to finish the work by Amy and Keith together = ?

Here,

∵ In 68 days the work done by Amy = 1

∴ In 1 day, the work done by Amy = 1/68 part

Similarly,

∵ In 73 days the work done by Keith = 1

∴ In 1 day, the work done by Keith = 1/73 part

Now, in 1 day, the work done by Amy and Keith together

= In 1 day work done by Amy + In 1 day the work done by Keith

= 1/68 + 1/73

= 73 + 68/4964

= 141/4964 part of work

This means in 1 day, 141/4964 part of work is done by Amy and Keith working together.

Now, the number of days required to finish 141/4964 part of work by Amy + Keith working together = 1

∴ the number of days required to finish 1 work by Amy + Keith together

= 1/141/4964

= 1 × 4964/141 = 4964/141 days

= 35 29/141 days = or 35.206 days

Thus, Amy and Keith working together will finish the work in 35 29/141 days = or 35.206 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 Amy = 68 days

And the number of days required to finish the same work by Keith = 73 days

Thus, the number of days required to finish the work Amy and Keith working together = ?

Here a = 68 days

And, b = 73 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Amy and Keith working together

= 68 × 73/68 + 73 days

= 4964/141 days

= 35 29/141 days or 35.206

Thus, Amy and Keith together will finish the work in 35 29/141 days or 35.206 days Answer


Similar Questions

(1) If Jennifer can finish the work in 7 days and Joseph can finish the same work in 11 days, then in how many days both can finish the work together?

(2) If Emily can finish the work in 40 days and Justin can finish the same work in 45 days, then in how many days both can finish the work together?

(3) Anthony can finish a work in 31 days. Donald can finish the same work in 36 days while Steven can finish the work in 41 days. How long will it take to finish it if they work together?

(4) Jessica can finish a work in 20 days. Karen can finish the same work in 25 days while Lisa can finish the work in 30 days. How long will it take to finish it if they work together?

(5) If Nancy can finish the work in 25 days and Ronald can finish the same work in 28 days, then in how many days both can finish the work together?

(6) Kenneth can finish a work in 41 days. Kevin can finish the same work in 42 days while Brian can finish the work in 43 days. How long will it take to finish it if they work together?

(7) If Michael can finish the work in 8 days and Thomas can finish the same work in 11 days, then in how many days both can finish the work together?

(8) Deborah can finish a work in 50 days. Stephanie can finish the same work in 51 days while Rebecca can finish the work in 52 days. How long will it take to finish it if they work together?

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