Car a leaves san diego at noon driving at 60 mph along a route which is 400 miles long to san francisco. car b leaves san francisco 2 hours later traveling along the same route at 80 mph. how far from the midpoint of the route are they when they meet? are they closer to san diego?

this is my question and i don't get what i'm supposed to do.. i don't know when they meet i'm not sure where to put the variables either.

Q1) jin loves carrot yesterday she ate ½ of here carrots and today she ate 2/3 of the remaining carrots. she then discover that she has 12 carrots left. yesterday she must has started with carrots? a)36 b)48 c)60 d)72

The biologist has a second culture to examine. she knows that the population of the culture doubles every 15 minutes. after 1 hour and 15 minutes, her assistant found that 80,000 bacteria were present. a) what was the size of the initial population? b) predict the size of the culture at t=3 hours. what was the size of the population at 40 minutes? explain and justify your answers. c) create a graph of the population as a function of time. find an equation that can be used to predict the size of the population at any time t. d) examine the rate at which the bacteria culture is growing. how fast is the culture growing after 1 hour? after 1.5 hours? after 2 hours? use a time interval of h = 0.01 hours to estimate these rates. interpret these rates in terms of the context of the problem situation. how do these three rates compare?

Find the value of x. also give me an explanation so i can complete it to other questions as well, : )