Question : A and B together can do a job in 15 days and A alone could do the same job in 20 days. How many days would B take to do half the job if he worked alone?
Option 1: 60
Option 2: 30
Option 3: 45
Option 4: 40
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: 30
Solution : A's job in one day can be expressed as $\frac{1}{20}$ of the total job. Assume that B completed $\frac{1}{y}$ of the entire job in a single day. According to the question, $\frac{1}{20}+\frac{1}{y}=\frac{1}{15}$ ⇒ $\frac{1}{y}=\frac{1}{15}-\frac{1}{20}$ ⇒ $\frac{1}{y}=\frac{4-3}{60}$ ⇒ $\frac{1}{y}=\frac{1}{60}$ ⇒ $y=60$ So, B will take 60 days to do the job. The half job will take $\frac{1}{2} \times60=30$ days to finish. Hence, the correct answer is 30.
Candidates can download this ebook to know all about SSC CGL.
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Question : If A and B together can do a piece of work in 20 days, and A alone can do the same work in 30 days, in how many days can B alone complete the same work?
Question : A completes 30% of a project in 30 days. He then calls in B and they together finish the remaining work in 20 days. How long would B alone take to do the whole work?
Question : A and B together can do a piece of work in 12 days, while A alone can do the same work in 30 days. B alone can do it in:
Question : A and B together can finish a work in 30 days. They worked on it for 20 days and then B left. The remaining work was done by A alone in 20 days. In how many days can A alone finish the work?
Question : A can do 20% of a job in 7 days and B can do 25% of the job in 7 days if they worked alone. How much of the job (in percentage) can they complete in 7 days if they worked together?
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile