Time and Work
MCQs Math


Question:     If Annie can finish a work in 2 days and Bobby can finish the same work in 3 days, then in how many days they both can finish the work working together?


Correct Answer  6/5 days or 11/5 days or 1.2 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Annie = 2 days

And, the number of days to finish the same work by Bobby = 3 days

Thus, the number of days to finish the work by Annie and Bobby working together = ?

Here, ∵ In 2 days the work done by Annie = 1

∴ In 1 day, the work done by Annie = 1/2 part

Similarly, ∵ In 3 days the work done by Bobby = 1

∴ In 1 day, the work done by Bobby = 1/3 part

Now, in 1 day, the work done by Annie and Bobby working together

= In 1 day work done by Annie + In 1 day the work done by Bobby

= 1/2 + 1/3

= 3 + 2/6

= 5/6

This means in 1 day, 5/6 part of work is done by Annie and Bobby working together.

Now, the number of days required to finish 5/6 part work by Annie + Bobby working together = 1

∴ the number of days required to finish 1 work by Robert + Bob working together

= 1/5/6

= 1 × 6/5 days = 6/5 days

= 6/5 or 1 1/5 days or 1.2 days

Thus, Annie and Bobby working together will finish the work in 6/5 or 1 1/5 days or 1.2 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 to finish the work by Annie = 2 days

And, the number of days to finish the same work by Bobby = 3 days

Thus, the number of days to finish the work by Annie and Bobby working together = ?

Here "a" = 2 days

And, "b" = 3 days

Thus, using formula a × b/a + b days

The number of days require to finish the work when Annie and Bobby working together

= 2 × 3/2 + 3

= 6/5 days or 11/5 days or 1.2 days

Thus, Annie and Bobby working together will finish the work in 6/5 days or 11/5 days or 1.2 days Answer


Similar Questions

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(2) If Carol can finish the work in 43 days and Alexander can finish the same work in 46 days, then in how many days both can finish the work together?

(3) 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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(6) If Emma can finish the work in 80 days and Jordan can finish the same work in 85 days, then in how many days both can finish the work together?

(7) Carolyn can finish a work in 96 days. Catherine can finish the same work in 101 days while Maria can finish the work in 106 days. How long will it take to finish it if they work together?

(8) Jack can finish a work in 99 days. Jerry can finish the same work in 104 days while Tyler can finish the work in 109 days. How long will it take to finish it if they work together?

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