Suppose 70% of kids who visit a doctor have a fever, and 45% of kids with a fever have sore throats. what's the probability that a kid who goes to the doctor has a fever and a sore throat?
i am stuck on this question, sadly i just did a lot of these for my exams but i forget how to solve it. someone ? ?

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. a new supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which size bag provides the best deal, and how much will you save each month? compare the cost of the new supplier to the current one.