Time and Work
MCQs Math


Question:     If Jacob can finish the work in 65 days and Noah can finish the same work in 70 days, then in how many days both can finish the work together?


Correct Answer  33 19/27 days or 33.704 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Jacob = 65 days

And, the number of days to finish the same work by Noah = 70 days

Thus, the number of days to finish the work by Jacob and Noah together = ?

Here,

∵ In 65 days the work done by Jacob = 1

∴ In 1 day, the work done by Jacob = 1/65 part

Similarly,

∵ In 70 days the work done by Noah = 1

∴ In 1 day, the work done by Noah = 1/70 part

Now, in 1 day, the work done by Jacob and Noah together

= In 1 day work done by Jacob + In 1 day the work done by Noah

= 1/65 + 1/70

= 14 + 13/910

= 27/910 part of work

This means in 1 day, 27/910 part of work is done by Jacob and Noah working together.

Now, the number of days required to finish 27/910 part of work by Jacob + Noah working together = 1

∴ the number of days required to finish 1 work by Jacob + Noah together

= 1/27/910

= 1 × 910/27 = 910/27 days

= 33 19/27 days = or 33.704 days

Thus, Jacob and Noah working together will finish the work in 33 19/27 days = or 33.704 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 Jacob = 65 days

And the number of days required to finish the same work by Noah = 70 days

Thus, the number of days required to finish the work Jacob and Noah working together = ?

Here a = 65 days

And, b = 70 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Jacob and Noah working together

= 65 × 70/65 + 70 days

= 4550/135 days

= 4550 ÷ 5/135 ÷ 5 = 910/27 days

= 33 19/27 days or 33.704

Thus, Jacob and Noah together will finish the work in 33 19/27 days or 33.704 days Answer


Similar Questions

(1) If Kenneth can finish the work in 42 days and Gregory can finish the same work in 46 days, then in how many days both can finish the work together?

(2) If Kathleen can finish the work in 66 days and Jeremy can finish the same work in 71 days, then in how many days both can finish the work together?

(3) If Annie can finish a work in 3 days and Bobby can finish the same work in 6 days, then in how many days they both can finish the work working together?

(4) David can finish a work in 9 days. William can finish the same work in 10 days while Richard can finish the work in 11 days. How long will it take to finish it if they work together?

(5) 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?

(6) 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?

(7) Kimberly can finish a work in 38 days. Donna can finish the same work in 43 days while Michelle can finish the work in 48 days. How long will it take to finish it if they work together?

(8) Andrew can finish a work in 41 days. Kenneth can finish the same work in 46 days while Kevin can finish the work in 51 days. How long will it take to finish it if they work together?

(9) If Mary can finish the work in 6 days and Michael can finish the same work in 11 days, then in how many days both can finish the work together?

(10) Donna can finish a work in 42 days. Carol can finish the same work in 47 days while Amanda can finish the work in 52 days. How long will it take to finish it if they work together?


NCERT Solution and CBSE Notes for class twelve, eleventh, tenth, ninth, seventh, sixth, fifth, fourth and General Math for competitive Exams. ©