Probability Math question help

Question

 A game of chance involves rolling a 14-sided die once. If a number from 1 to 3 comes up, you win 2 dollars. If the number 4 or 5 comes up, you win 7 dollars. If any other number comes up, you lose. If it costs 4 dollars to play, what is your expected net winnings?

-answer is not 14.1 or 14.2

Answer 1

Hi Bella B.,

Let's see what I come up with. Stake to play = $4. Expected total return (winnings*probability of obtaining) = ((3 *$ 2)+(2*$7))/14 = ($20/14). So on the average you net: 10/7 - 4 = lose $2.57 .

-- Cheers, -- Mr. d.