Time and Work
MCQs Math


Question:     If Thomas can finish the work in 21 days and Andrew can finish the same work in 26 days, then in how many days both can finish the work together?


Correct Answer  11 29/47 days or 11.617 days

Solution And Explanation

Solution

Given,

The number of days to finish the work by Thomas = 21 days

And, the number of days to finish the same work by Andrew = 26 days

Thus, the number of days to finish the work by Thomas and Andrew together = ?

Here,

∵ In 21 days the work done by Thomas = 1

∴ In 1 day, the work done by Thomas = 1/21 part

Similarly,

∵ In 26 days the work done by Andrew = 1

∴ In 1 day, the work done by Andrew = 1/26 part

Now, in 1 day, the work done by Thomas and Andrew together

= In 1 day work done by Thomas + In 1 day the work done by Andrew

= 1/21 + 1/26

= 26 + 21/546

= 47/546 part of work

This means in 1 day, 47/546 part of work is done by Thomas and Andrew working together.

Now, the number of days required to finish 47/546 part of work by Thomas + Andrew working together = 1

∴ the number of days required to finish 1 work by Thomas + Andrew together

= 1/47/546

= 1 × 546/47 = 546/47 days

= 11 29/47 days = or 11.617 days

Thus, Thomas and Andrew working together will finish the work in 11 29/47 days = or 11.617 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 Thomas = 21 days

And the number of days required to finish the same work by Andrew = 26 days

Thus, the number of days required to finish the work Thomas and Andrew working together = ?

Here a = 21 days

And, b = 26 days

Thus, using formula a × b/a + b days

The number of days required to finish the work when Thomas and Andrew working together

= 21 × 26/21 + 26 days

= 546/47 days

= 11 29/47 days or 11.617

Thus, Thomas and Andrew together will finish the work in 11 29/47 days or 11.617 days Answer


Similar Questions

(1) Catherine can finish a work in 100 days. Heather can finish the same work in 105 days while Diane can finish the work in 110 days. How long will it take to finish it if they work together?

(2) William can finish a work in 15 days. Joseph can finish the same work in 20 days while Thomas can finish the work in 25 days. How long will it take to finish it if they work together?

(3) Scott can finish a work in 81 days. Benjamin can finish the same work in 86 days while Samuel can finish the work in 91 days. How long will it take to finish it if they work together?

(4) 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?

(5) Rachel can finish a work in 94 days. Janet can finish the same work in 99 days while Catherine can finish the work in 104 days. How long will it take to finish it if they work together?

(6) Helen can finish a work in 84 days. Katherine can finish the same work in 89 days while Christine can finish the work in 94 days. How long will it take to finish it if they work together?

(7) Matthew can finish a work in 29 days. Mark can finish the same work in 34 days while Donald can finish the work in 39 days. How long will it take to finish it if they work together?

(8) If Patricia can finish the work in 5 days and William can finish the same work in 8 days, then in how many days both can finish the work together?

(9) 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?

(10) If Joshua can finish the work in 40 days and Benjamin can finish the same work in 43 days, then in how many days both can finish the work together?


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