7 Views

Question : A can do a piece of work in 8 days which B can destroy in 3 days. A has worked for 6 days, during the last 2 days of which B has been destroying; how many days must A work alone to complete the remaining work?

Option 1: $7\ \text{days}$

Option 2: $7\frac{1}{3}\ \text{days}$

Option 3: $7\frac{2}{3}\ \text{days}$

Option 4: $8\ \text{days}$


Team Careers360 18th Jan, 2024
Answer (1)
Team Careers360 19th Jan, 2024

Correct Answer: $7\frac{1}{3}\ \text{days}$


Solution : Time taken by A alone to do the work = 8 days
Part of work done by A alone in a day = $\frac{1}{8}$
Time taken by B alone to destroy the work = 3 days
Part of work destroyed by B alone in a day = $\frac{1}{3}$
Part of work done by A in 6 days = $\frac{6}{8}$
Part of work destroyed by B in last 2 days = $\frac{2}{3}$
Part of work completed after 6 days = $\frac{6}{8}-\frac{2}{3}$ = $\frac{18-16}{24}$ = $\frac{2}{24}$
Remaining part of work to be completed by A alone = $1-\frac{2}{24}$ = $\frac{22}{24}$
So, the number of days needed to complete the remaining work by A alone = $\frac{\frac{22}{24}}{\frac{1}{8}}$ = $\frac{22}{3}$ = $7\frac{1}{3}\ \text{days}$
Hence, the correct answer is $7\frac{1}{3}\ \text{days}$.

Know More About

Related Questions

TOEFL ® Registrations 2024
Apply
Accepted by more than 11,000 universities in over 150 countries worldwide
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
GRE ® Registrations 2024
Apply
Apply for GRE® Test now & save 10% with ApplyShop Gift Card | World's most used Admission Test for Graduate & Professional Schools
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books