Simplify -2/5 + 4/3. What is the answer?

What is the first step of an indirect proof of a number that is divisible by two

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?

Aefg - almn. find the ratio of aefg to almn. a)1: 4 b)1: 2 c)2.1 d)4: 1