Question 1: car a began a journey from a point at 9 am, traveling at 30 mph. at 10 am car b started traveling from the same point at 40 mph in the same direction as car a. at what time will car b pass car a?
solution:
let after t hours the distances d1 traveled by car a
=> d1 = 30 t
car b starts at 10 am and will therefore have spent one hour less than car a when it passes it.
after (t - 1) hours, distance d2 traveled by car b
=> d2 = 40 (t - 1)
when car b passes car a, they are at the same distance from the starting point and therefore d1 = d2
=> 30 t = 40 (t - 1)
solve the equation for t,