Question

(1) Find the speed of car X and car Y.
(ii) When and where will car Y catch car X?​

Answer 1

Explanation:

(1) The speed of car X is (distance)/(time) = 80/2 = 40 miles per hour. The speed of car Y = 3/2*40 = 60 miles per hour --> (time) = (distance)/(speed) = 80/60 = 4/3 hours.

(2) Let speed of Y = V ,

speed of X = 1.5 V,

relative speed of X wrt Y (catch up speed of X) = 0.5V.

Now catch up speed = (distance between X and Y)/time.

0.5 V = 40 miles / (8/3 hour),

so V = 30 miles/hr.

However, what I don't understand is that the distance traveled by Car Y while Car X is catching up is not factored into the problem. Could someone clarify if my concern is valid, if not then reason.