How can we describe the parts of the expression that the arrows point to?

Can any one me with the answers to these questions asap?

Olga used 100 ounces of flour to make 225 muffins. how many ounces of flour will be used to make 300 muffins?

You were told that the amount of time lapsed between consecutive trades on the new york stock exchange followed a normal distribution with a mean of 15 seconds. you were also told that the probability that the time lapsed between two consecutive trades to fall between 16 to 17 seconds was 13%. the probability that the time lapsed between two consecutive trades would fall below 13 seconds was 7%. what is the probability that the time lapsed between two consecutive trades will be between 14 and 15 seconds?