Max a graduating senior, has accumulated an impressive file of tests during his college career. But now, he needs to sell his test collection to obtain money for his marriage. 3 rich friends express interest in buying some of the tests. Max determines that their individual demand equations are as follows:

Q1=30-P (Qd for friend no.1)

Q2=22.50-0.75P (Qd for friend no.2)

Q3=37.50-1.25P (Qd for friend no.3)

a)What us the market demand,Qm for Max's tests collection?

b)How many more tests collection can he sell for each $1 decrease in price?

c)If he has 60 tests collection and he wants to sell all of them,at what price should he charge?