Time and Work
Math MCQs

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 & 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) 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?

(2) Ashley can finish a work in 36 days. Emily can finish the same work in 41 days while Donna can finish the work in 46 days. How long will it take to finish it if they work together?

(3) If Thomas can finish the work in 18 days and Andrew can finish the same work in 22 days, then in how many days both can finish the work together?

(4) If David can finish the work in 10 days and Christopher can finish the same work in 13 days, then in how many days both can finish the work together?

(5) If Sarah can finish the work in 19 days and Joshua can finish the same work in 22 days, then in how many days both can finish the work together?

(6) 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?

(7) Paul can finish a work in 35 days. Andrew can finish the same work in 36 days while Joshua can finish the work in 37 days. How long will it take to finish it if they work together?

(8) If Deborah can finish the work in 54 days and Aaron can finish the same work in 59 days, then in how many days both can finish the work together?

(9) If Raymond can finish the work in 97 days and Eugene can finish the same work in 102 days, then in how many days both can finish the work together?

(10) If Matthew can finish the work in 29 days and Edward can finish the same work in 34 days, then in how many days both can finish the work together?