What i did is that i did $1.50 time 8 = $12.00 and then do $30.00-12.00=$18.00
The direct answer to your question is: "No".
because in that equation, 'x' is not 120 or130.
Let's find out what 'x' actually is:
<u>3/5 x = 52</u>
Multiply each side by 5 : 3x = 260
Divide each side by 3 : <em> x = 86 and 2/3 </em>
9x squared - 6x - 6x + 4
9x squared - 12x + 4
Well this is pretty simple. So the first thought is that the peanut butter would be 10$ and the jam would be 0.20$, however, the peanut butter would not be 10$ more. Instead, subtract the 10$ from the total, which gives you 0.20$, and then divide that by two. Now you have 0.10$ for each, along with another 10$ for the peanut butter. The peanut butter would be $10.10, and the jam would be 0.10$ (that's pretty cheap!).
Expected value of the bet is
the sum of the products of value of outcome and its probability,
less the amount paid to place the bet.
Outcomes value probability
win 225 1/4
lose 0 3/4
cost of bet = 40
So expected value of bet
E[X]=225*(1/4)+0*(3/4)-40
=56.25-40
=16.25
This means that in the long run, gambler will win, since the expected value is positive. (does NOT mean she will win in the next bet!)