How do I solve this rate law problem?

Question

A reaction has the experimental rate law of  rate=k [A]^2

 

A. What happens to the rate if the concentration of A is tripled?

 

B. What happens to the rate if the concentration of A is  reduced to one third the inital concentration?

 

Answer 1

If you triple the concentration of A, the rate will increase by a factor of 3^2 or 9. 

If you reduce the concentration of A to 1/3 the rate will decrease by a factor of (1/3)^2 or 1/9.