A car leaves Macomb traveling south toward Carbondale at the average rate of 52 mph. At the same time, another car leaves Springfield traveling north toward Chicago at the average rate of 60 mph. If they are traveling the same high way, but going different directions, how long will it take them to meet if the cities are 252 miles apart?

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)

we need to see the graph to know but

strong positive is if it is going up from left to right in a straight diagonal line (like this /)

strong negative is the same but from right to left (like this \)

weak negative is the same as strong negative but its more straight line still right to left

and weak positive is the same as strong positive but more a straight line still left to right though.