SOLUTION: A cat on seeing a dog 100m away turns around and start running away at 24 kmph.The dog spots him one minute later and start chasing the cat at a speed of 33kmph.After how much time

                SPEED      TIME           DISTANCE
CAT             24         t+(1/60)          d
DOG             33          t              d+0.1

The speed of the cat is 24 km/h, which is  = 400 meters per minute.

Therefore, the initial distance between the cat and the dog was 

100 m + 400 m = 500 meters. (400 m was the distance the cat run away in one minute before the dog started chasing the cat)

The distance between the dog and the cat is decreasing in 33-24 = 9 km per hour, which is  = 150 meters per minute.

Hence, the dog will catch the cat in  =   minutes = 3 minutes and 20 seconds after the dog starts, 
                                                       or in 4 minutes and 20 seconds after the cat start.

I wish the cat to find the tall tree before the dog will catch him.

I don't do diagrams. Sorry. You have to visualize it and draw your own diagram.



Let time the cat takes to get to the catch point be T

Then time dog takes to get to catch up point = 

Since they’re travelling in km, then distance between the 2 is: .1 km (100 m)

We then get the following DISTANCE equation: 





480T – 660T = - 11 - 2 -------- Multiplying by LCD, 20

- 180T = - 13

T, or time the chase ended (dog caught up), from the time the cat started running =