It will take 18 days for Cameron to complete a certain task alone. He worked for 9 days before she was joined by Sandra. both of them completed the remaining task in 3 and half days. how many days will it take both of them to complete the entire job?	Answers
A) 6	B) 7	C) 5	D) 8	E) 9

Rationale: explanation : cameron and sandra completed half work in 3.5 days = > they can complete whole work in 7 days answer : option b
Answer: B