Two families go to a zoo. The Smith family of two adults and three children pay £61.
The Jones family of three adults and five children pay £96.
Work out the cost of an adult ticket and the cost of a child ticket.
In your working, let 'a' stand for an adult ticket and 'c' stand for a child ticket.

An oil exploration company currently has two active projects, one in asia and the other in europe. let a be the event that the asian project is successful and b be the event that the european project is successful. suppose that a and b are independent events with p(a) = 0.2 and p(b) = 0.8. (a) if the asian project is not successful, what is the probability that the european project is also not successful? (b) what is the probability that at least one of the two projects will be successful? (c) given that at least one of the two projects is successful, what is the probability that only the asian project is successful? (round your answer to three decimal places.)