Time and Work
MCQs Math


Question:     If Benjamin can finish the work in 85 days and Gabriel can finish the same work in 90 days, then in how many days both can finish the work together?


Correct Answer  43 5/7 days or 43.714 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Benjamin = 85 days

And, the number of days to finish the same work by Gabriel = 90 days

Thus, the number of days to finish the work by Benjamin and Gabriel together = ?

Here,

∵ In 85 days the work done by Benjamin = 1

∴ In 1 day, the work done by Benjamin = 1/85 part

Similarly,

∵ In 90 days the work done by Gabriel = 1

∴ In 1 day, the work done by Gabriel = 1/90 part

Now, in 1 day, the work done by Benjamin and Gabriel together

= In 1 day work done by Benjamin + In 1 day the work done by Gabriel

= 1/85 + 1/90

= 18 + 17/1530

= 35/1530 part of work

= 35 ÷ 5/1530 ÷ 5 part of work

= 7/306 part of work

This means, in 1 day, 7/306 part of the work is done by Benjamin and Gabriel together.

Now, the number of days required to finish 7/306 part of work by Benjamin + Gabriel working together = 1

∴ the number of days required to finish 1 work by Benjamin + Gabriel together

= 1/7/306

= 1 × 306/7 = 306/7 days

= 43 5/7 days = or 43.714 days

Thus, Benjamin and Gabriel working together will finish the work in 43 5/7 days = or 43.714 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 Benjamin = 85 days

And the number of days required to finish the same work by Gabriel = 90 days

Thus, the number of days required to finish the work Benjamin and Gabriel working together = ?

Here a = 85 days

And, b = 90 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Benjamin and Gabriel working together

= 85 × 90/85 + 90 days

= 7650/175 days

= 7650 ÷ 25/175 ÷ 25 = 306/7 days

= 43 5/7 days or 43.714

Thus, Benjamin and Gabriel together will finish the work in 43 5/7 days or 43.714 days Answer


Similar Questions

(1) 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?

(2) If Barbara can finish the work in 13 days and Anthony can finish the same work in 16 days, then in how many days both can finish the work together?

(3) If Dorothy can finish the work in 50 days and Jack can finish the same work in 55 days, then in how many days both can finish the work together?

(4) Pamela can finish a work in 78 days. Nicole can finish the same work in 83 days while Helen can finish the work in 88 days. How long will it take to finish it if they work together?

(5) If Andrew can finish the work in 38 days and Scott can finish the same work in 42 days, then in how many days both can finish the work together?

(6) If Daniel can finish the work in 27 days and Timothy can finish the same work in 32 days, then in how many days both can finish the work together?

(7) Anthony can finish a work in 27 days. Mark can finish the same work in 28 days while Donald can finish the work in 29 days. How long will it take to finish it if they work together?

(8) If Jack can finish a work in 8 days and Bill can finish the same work in 12 days, then in how many days they both can finish the work working together?

(9) If Joshua can finish the work in 40 days and Benjamin can finish the same work in 44 days, then in how many days both can finish the work together?

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