Stephen H. answered 11/26/14
AP Calculus AB/BC, GED & more - M.Ed. w/ 10+ yrs of experience
Ivy, The expected value from a wager should be found by adding each of the individuals probabilities times the amount earned, lost, or not gained. Here, we use the variable "w" for the amount of your wager: E(w)=0.2(1.5w)+0.4(w)+0.2(-2w)+0.2(0) This simplifies to E(w)=0.3w+0.4w-0.4w+0w or E(w)=0.3w. So, if you wagered $1, you'd expect to win 30 cents or $0.30 because E($1)=0.3($1)=$0.3. In the general sense, you'd expect to win 30% of what your wager was.
Ivy C.
11/26/14