JOHN and ANDREW can finish the work 9 days if they work together. They worked together for 6 days and then ANDREW left. JOHN finished the remaining work in another 6 days. In how many days JOHN alone can finish the work?	Choose the correct option
A) 30 days  B) 60 days  C) 18 days  D) 80 days  E) 90 days
Amount of work done by JOHN and ANDREW in 1 day = 1/9   Amount of work done by JOHN and ANDREW in 6 days = 6 Ã— (1/9) = 2/3   Remaining work â€“ 1 â€“ 2/3 = 1/3   JOHN completes 1/3 work in 6 days   Amount of work JOHN can do in 1 day = (1/3)/6 = 1/18   =&gt; JOHN can complete the work in 18 days   Answer : 18 days
<result>C</result>
JOHN and ANDREW can finish the work 9 days if they work together. They worked together for 6 days and then ANDREW left. JOHN finished the remaining work in another 6 days. In how many days JOHN alone can finish the work?