Expected Value Question

Question

A business man evaluated a proposed venture. He estimated that the probability of making a profit of $9000 is 0.2; the probability of making $5000 is 0.4; the probability of breaking even is 0.3; and the probability of losing $4000 is 0.1. Find his expected profit.

Answer 1

sum of x * P(x) = 9000*0.2 + 5000*0.4 + 0*0.3 - 4000*0.1 = 3400