# calculus

posted by
**ellie**
.

A police car is driving northward, chasing a vehicle which has just taken a right turn at an intersection, and is travelling due west. When the police car is 600 yards south of the intersection, and the car is 800 yards east of the intersection, an aerial speed radar indicates that the distance between the two cars is increasing by 20 mph. If the police car is travelling at 60 mph when the measurment is taken, how fast is the other car going?