Time and Work
MCQs Math


Question:     If George can finish the work in 48 days and Dennis can finish the same work in 52 days, then in how many days both can finish the work together?


Correct Answer  24 24/25 days or 24.96 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by George = 48 days

And, the number of days to finish the same work by Dennis = 52 days

Thus, the number of days to finish the work by George and Dennis together = ?

Here,

∵ In 48 days the work done by George = 1

∴ In 1 day, the work done by George = 1/48 part

Similarly,

∵ In 52 days the work done by Dennis = 1

∴ In 1 day, the work done by Dennis = 1/52 part

Now, in 1 day, the work done by George and Dennis together

= In 1 day work done by George + In 1 day the work done by Dennis

= 1/48 + 1/52

= 13 + 12/624

= 25/624 part of work

This means in 1 day, 25/624 part of work is done by George and Dennis working together.

Now, the number of days required to finish 25/624 part of work by George + Dennis working together = 1

∴ the number of days required to finish 1 work by George + Dennis together

= 1/25/624

= 1 × 624/25 = 624/25 days

= 24 24/25 days = or 24.96 days

Thus, George and Dennis working together will finish the work in 24 24/25 days = or 24.96 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 George = 48 days

And the number of days required to finish the same work by Dennis = 52 days

Thus, the number of days required to finish the work George and Dennis working together = ?

Here a = 48 days

And, b = 52 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when George and Dennis working together

= 48 × 52/48 + 52 days

= 2496/100 days

= 2496 ÷ 4/100 ÷ 4 = 624/25 days

= 24 24/25 days or 24.96

Thus, George and Dennis together will finish the work in 24 24/25 days or 24.96 days Answer


Similar Questions

(1) If Robert can finish a work in 5 days and Bob can finish the same work in 6 days, then in how many days they both can finish the work working together?

(2) If Mary can finish the work in 25 days and Michael can finish the same work in 41 days, then in how many days both can finish the work together?

(3) Kevin can finish a work in 47 days. George can finish the same work in 52 days while Timothy can finish the work in 57 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 48 days, then in how many days both can finish the work together?

(5) If Donald can finish the work in 32 days and Nicholas can finish the same work in 35 days, then in how many days both can finish the work together?

(6) Emma can finish a work in 80 days. Helen can finish the same work in 85 days while Samantha can finish the work in 90 days. How long will it take to finish it if they work together?

(7) If Nicholas can finish the work in 69 days and Roger can finish the same work in 74 days, then in how many days both can finish the work together?

(8) If John can finish the work in 6 days and Richard can finish the same work in 10 days, then in how many days both can finish the work together?

(9) If Sandra can finish the work in 34 days and Gary can finish the same work in 39 days, then in how many days both can finish the work together?

(10) Ronald can finish a work in 55 days. Jason can finish the same work in 60 days while Jeffrey can finish the work in 65 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. ©