Average speed of car 1 = 45 mph.
average speed of car 2 = 65 mph.
time elapsed between start of car 1 and start of car 2 = 18 minutes.
how long before car 2 overtakes car 1?
a. 0.68
b. 0.53
c. 0.58

Ok, note to a mod who deleted my answer, it would have been nice to ask for correction first (or maybe I wasn't online long enough to see?) so I can improve and see what went wrong

how long before car2overtakes car1,

since car2 is faster than car1, we assume that car1 left first
it left 18 minutes first

find how much distance that is
45 times hours=distance
60minsperhour
45 times 18/45=distance=13.5
headstart of 13.5miles

so

their distances are reprsetned by

45h+13.5=car1distance at h hours AFTER 18 minutes
65h=car2 disstance at h hours AFTER 18 minutes

when will distance be same?
set equal to each other

45h+13.5=65h
minus 45h both sides
13.5=20h
divide oth side by 20
0.675=h
0.675 hours

we round
0.68

answer is 0.68 hours
(note again, if  you want to delete my answer or see something wrong with this answer, tell me what it is so I can improve and learn (or maybe I can show you where you are wrong))

A is answer