Time and Work
MCQs Math


Question:     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?


Correct Answer  28 13342/22163 days or 28.602 days

Solution And Explanation

Solution

Given,

The number of days required to finish a piece of work by Scott = 81 days

And, the number of days required to finish the same work by Benjamin = 86 days

And, the number of days required to finish the same work by Samuel = 91 days

Thus, the number of days required to finish the work by all of them if they work together = ?

Here,

∵ In 81 days the work is done by Scott = 1

∴ The work done by Scott in 1 day = 1/81

Similarly,

∵ In 86 days the work is done by Benjamin = 1

∴ The work done by Benjamin in 1 day = 1/86

Similarly,

∵ In 91 days the work is done by Samuel = 1

∴ The work done by Samuel in 1 day = 1/91 part

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

= Scott's 1 day work + Benjamin's 1 day work + Samuel's 1 day work

= 1/81 + 1/86 + 1/91

= 7826 + 7371 + 6966/633906

= 22163/633906 part of work

This means in 1 day, 22163/633906 part of work is done by Scott, Benjamin and Samuel working together.

Now, the number of days required to finish 22163/633906 part of work by Scott, Benjamin, and Samuel working together = 1

∴ the number of days required to finish the whole work (1 work) by Scott + Benjamin + Samuel together

= 1/22163/633906

= 1 × 633906/22163 = 633906/22163 days

= 28 13342/22163 days = or 28.602 days

Thus, Scott, Benjamin, and Samuel working together will finish the total work (1 work) in 28 13342/22163 days = or 28.602 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, B can finish the same work in b days, and C can finish the work in c days
then working together the number of days required to finish the work
= a × b × c/ab + ac + bc days.

Here given,

The number of days required to finish the work by Scott = 81 days

And the number of days required to finish the same work by Benjamin = 86 days

And the number of days required to finish the work by Samuel = 91 days

Thus, the number of days required to finish the work by Scott, Benjamin, and Samuel together = ?

Here a = 81 days

And, b = 86 days

And, c = 91 days

Thus, using formula a × b × c/ab + ac + bc days

The number of days required to finish the work when Scott, Benjamin, and Samuel working together

= 81 × 86 × 91/81 × 86 + 81 × 91 + 86 × 91 days

= 633906/6966 + 7371 + 7826 days

= 633906/22163 days

= 633906/22163 days

= 28 13342/22163 days or 28.602

Thus, Scott, Benjamin, and Samuel together will finish the work in 28 13342/22163 days or 28.602 days Answer


Similar Questions

(1) If James can finish the work in 2 days and John can finish the same work in 5 days, then in how many days both can finish the work together?

(2) If Ashley can finish the work in 33 days and Eric can finish the same work in 36 days, then in how many days both can finish the work together?

(3) If John can finish the work in 9 days and Richard can finish the same work in 14 days, then in how many days both can finish the work together?

(4) If Kenneth can finish the work in 45 days and Gregory can finish the same work in 50 days, then in how many days both can finish the work together?

(5) Thomas can finish a work in 21 days. Christopher can finish the same work in 26 days while Daniel can finish the work in 31 days. How long will it take to finish it if they work together?

(6) If Matthew can finish the work in 26 days and Edward can finish the same work in 29 days, then in how many days both can finish the work together?

(7) Samuel can finish a work in 87 days. Alexander can finish the same work in 92 days while Frank can finish the work in 97 days. How long will it take to finish it if they work together?

(8) 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?

(9) Brenda can finish a work in 76 days. Emma can finish the same work in 81 days while Nicole can finish the work in 86 days. How long will it take to finish it if they work together?

(10) If Brandon can finish the work in 83 days and Joe can finish the same work in 88 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. ©