If he is 4 now is in 10 years he will be 14 and if you multiply that by 2 you get 28 which means in 10 years Marie will be 28 so that means if you take away 10 the answer should be 18 but that isn't there but that's how I would work it out.
standard deviation of 1 minute, find the probability that a randomly selected college
Your answer to fill in the blank should be "interactions"