Roberto left his parent's house at 11 a. m. traveling at an average rate of 30 mph. his parents left their house at 12 p. m. traveling at an average rate of 45 mph going the same way as roberto so that they could catch up to him. after how many hours will it take roberto's parents to catch up to him?
how do i set up this equation?

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Which table represents points on the graph of h(x) = 3√-x+2?