1- If you ran 12 laps around the track in 4 minutes, what is the unit rate? 2- Lin bought 3 hats for $22.50. At this rate, how many hats could she buy with $60.00?
3- Sue and Jim are driving on the highway. Sue takes 24 minutes to drive 40 km. If Jim drives at the same rate, how long will it take for him to drive 115 km?
4- James blinked his eyes 18 times in 20 seconds. At this rate, how many times could James blink his eyes in 1 minute

The height BC of the cliff is 400 m

Step-by-step explanation:

Let the distance between the point A to the cliff at B is x meters and the height BC is y meters.

So, x + y = 500 ....... (1)

⇒ 4x + 4y = 2000 .......... (2)

Now, at the speed of 4 m/s the time of travel from points A to B is sec. and at a rate of fall of 25 m/s the times taken to fall from B to C will be sec.

So, from the conditions given we can write  

....... (3)

⇒ 25x + 4y = 4100 ........ (4)

Now, solving equations (2) and (4) we get  

21x = 2100

⇒ x = 100 m

So,  from equation (1) we can write y = (500 - 100) = 400 m.

Therefore, the height BC of the cliff is 400 m (Answer)