Expected value help

$30 goes to the organizer. That means they get $1.50 per ticket

Let X = amount you can win/lose.
X can be (80-p) or -p where p is the price for the ticket not counting the additional $1.50

Want E(X) = (80-p)(1/20) - p(19/20) = 0
So (80-p)-(19p) = 80 - 20p = 0
So 20p = 80 and p=4.

The total cost per ticket is $(4+1.5) = $5.50

Check: 20*$5.50 = $110 total collected. $30 goes to the organizer leaving $80 for the winner.
 
$30 goes to the organizer. That means they get $1.50 per ticket

Let X = amount you can win/lose.
X can be (80-p) or -p where p is the price for the ticket not counting the additional $1.50

Want E(X) = (80-p)(1/20) - p(19/20) = 0
So (80-p)-(19p) = 80 - 20p = 0
So 20p = 80 and p=4.

The total cost per ticket is $(4+1.5) = $5.50

Check: 20*$5.50 = $110 total collected. $30 goes to the organizer leaving $80 for the winner.
thanks!!
 
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