Time and Work
MCQs Math


Question:     If Myra can finish the work in 25 days and Sophia can finish the same work in 15 days, then in how many days they both can finish the work working together?


Correct Answer  9 3/8 days or 9.375 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Myra = 25 days

And, the number of days to finish the same work by Sophia = 15 days

Thus, the number of days to finish the work by Myra and Sophia working together = ?

Here, ∵ In 25 days the work done by Myra = 1

∴ In 1 day, the work done by Myra = 1/25 part

Similarly, ∵ In 15 days the work done by Sophia = 1

∴ In 1 day, the work done by Sophia = 1/15 part

Now, in 1 day, the work done by Myra and Sophia working together

= In 1 day work done by Myra + In 1 day the work done by Sophia

= 1/25 + 1/15

= 3 + 5/75

= 8/75 part of work

This means in 1 day, 8/75 part of work is done by Myra and Sophia working together.

Now, the number of days required to finish 8/75 part of work by Myra + Sophia working together = 1

∴ the number of days required to finish 1 work by Myra + Sophia working together

= 1/8/75

= 1 × 75/8 = 75/8 days

= 93/8 days = 9.375 days

Thus, Myra and Sophia working together will finish the work in 93/8 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 Myra = 25 days

And, the number of days to finish the same work by Sophia = 15 days

Thus, the number of days to finish the work by Myra and Sophia working together = ?

Here "a" = 25 days

And, "b" = 15 days

Thus, using formula a × b/a + b days

The number of days require to finish the work when Myra and Sophia working together

= 25 × 15/25 + 15 days

= 375/40 days

= 75 × 5/8 × 5 = 75/8 days

= 9 3/8 days or 9.375 days

Thus, Myra and Sophia working together will finish the work in 9 3/8 days or 9.375 days Answer


Similar Questions

(1) Elizabeth can finish a work in 14 days. Susan can finish the same work in 19 days while Jessica can finish the work in 24 days. How long will it take to finish it if they work together?

(2) If Karen can finish the work in 24 days and Kevin can finish the same work in 29 days, then in how many days both can finish the work together?

(3) 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?

(4) If Lisa can finish the work in 23 days and George can finish the same work in 27 days, then in how many days both can finish the work together?

(5) Ashley can finish a work in 32 days. Kimberly can finish the same work in 33 days while Emily can finish the work in 34 days. How long will it take to finish it if they work together?

(6) If Matthew can finish the work in 26 days and Edward can finish the same work in 30 days, then in how many days both can finish the work together?

(7) If Christopher can finish the work in 25 days and Brian can finish the same work in 30 days, then in how many days both can finish the work together?

(8) If Sandra can finish the work in 31 days and Gary can finish the same work in 35 days, then in how many days both can finish the work together?

(9) If Joshua can finish the work in 43 days and Benjamin can finish the same work in 48 days, then in how many days both can finish the work together?

(10) If Myra can finish the work in 25 days and Sophia can finish the same work in 15 days, then in how many days they both can finish the work working together?


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