The altitude of a triangle is increasing at a rate of 1 cm/min while the area of the triangle is ...

The altitude of a triangle is increasing at a rate of 1 cm/min while the area of the triangle is increasing at a rate of 2 cm2/min. At what rate is the base of the triangle changing when the altitude is 10 cm and the area is 100 cm2?
Answer: -1.6 cm/min
Textbook: Single Variable Calculus by James Stewart (fourth edition)
Page 204, question #13