Suppose that the demand for water balloons fit the function D(p,ps)= .2 p-0.5ps-0.2; where p is the

Question:

Suppose that the demand for water balloons fit the function D(p,ps)= .2 p-0.5ps-0.2; where p is the price of water balloons and ps is the price of super soakers (an advanced squirt gun technology).
Based upon this demand curve, are super soakers a compliment or a substitute for water balloons? Demonstrate why.