Time and Work
MCQs Math


Question:     If Gary can finish the work in 67 days and Christian can finish the same work in 72 days, then in how many days both can finish the work together?


Correct Answer  34 98/139 days or 34.705 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Gary = 67 days

And, the number of days to finish the same work by Christian = 72 days

Thus, the number of days to finish the work by Gary and Christian together = ?

Here,

∵ In 67 days the work done by Gary = 1

∴ In 1 day, the work done by Gary = 1/67 part

Similarly,

∵ In 72 days the work done by Christian = 1

∴ In 1 day, the work done by Christian = 1/72 part

Now, in 1 day, the work done by Gary and Christian together

= In 1 day work done by Gary + In 1 day the work done by Christian

= 1/67 + 1/72

= 72 + 67/4824

= 139/4824 part of work

This means in 1 day, 139/4824 part of work is done by Gary and Christian working together.

Now, the number of days required to finish 139/4824 part of work by Gary + Christian working together = 1

∴ the number of days required to finish 1 work by Gary + Christian together

= 1/139/4824

= 1 × 4824/139 = 4824/139 days

= 34 98/139 days = or 34.705 days

Thus, Gary and Christian working together will finish the work in 34 98/139 days = or 34.705 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 Gary = 67 days

And the number of days required to finish the same work by Christian = 72 days

Thus, the number of days required to finish the work Gary and Christian working together = ?

Here a = 67 days

And, b = 72 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Gary and Christian working together

= 67 × 72/67 + 72 days

= 4824/139 days

= 34 98/139 days or 34.705

Thus, Gary and Christian together will finish the work in 34 98/139 days or 34.705 days Answer


Similar Questions

(1) Lisa can finish a work in 22 days. Nancy can finish the same work in 23 days while Betty can finish the work in 24 days. How long will it take to finish it if they work together?

(2) 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?

(3) Richard can finish a work in 17 days. Thomas can finish the same work in 22 days while Charles can finish the work in 27 days. How long will it take to finish it if they work together?

(4) If Kevin can finish the work in 44 days and Frank can finish the same work in 47 days, then in how many days both can finish the work together?

(5) If Susan can finish the work in 15 days and Donald can finish the same work in 19 days, then in how many days both can finish the work together?

(6) If Catherine can finish the work in 100 days and Mason can finish the same work in 105 days, then in how many days both can finish the work together?

(7) Justin can finish a work in 79 days. Brandon can finish the same work in 84 days while Benjamin can finish the work in 89 days. How long will it take to finish it if they work together?

(8) Daniel can finish a work in 23 days. Matthew can finish the same work in 24 days while Anthony can finish the work in 25 days. How long will it take to finish it if they work together?

(9) If Emily can finish the work in 37 days and Justin can finish the same work in 41 days, then in how many days both can finish the work together?

(10) If Jeffrey can finish the work in 61 days and Peter can finish the same work in 66 days, then in how many days both can finish the work together?


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