First one is wrong bcs it should be smaller than the answer.
The second one is correct bcs to find the second number we need to do inverse operation, here is subtraction.
Third one is correct bcs this is the same (but if u r searching only for relating not same, then the third kind of wrong)
The last one is correct
Answer:
I am not sure but for me the answer is 1
Answer:
And the cost of play would be 1 with probability 1 for any given game. Then we can find the expected value like this:

And solving we got:

And then the best answer for this case would be:
$1.50
Step-by-step explanation:
For this case we can calculate the expected value with this formula:

We assume that the standard deck is formed just with red and black cards. For this case we have the following info:
And the cost of play would be -1 with probability 1 for any given game. Then we can find the expected value like this:

And solving we got:

And then the best answer for this case would be:
$1.50