1. The altitude (height) of a triangle is increasing at a rate of
2cm/min while the area is increasing at a rate of 3cm2 /min . What is the rate of change of the base of the triangle at the time when the height is 15 cm, and the area is 175cm2 ?

I ended up with b=23.33cm and my ROC is -2.7 cm/min

2. A trough is 10ft long and its ends have the shape
of isosceles triangles that are
4ft across the top and have a
height of
5ft . If the trough is being filled with water at a rate
12ft3/min, how fast is the water level rising when the

water is
30in deep?

For this I got a ROC in water level of .6ft/min

These seem straight forward but thats typically where I make a dumb mistake