I do believe that the answer is 9.<span />
Given:
• AD = 3
,
• DC = 27
,
• BD = x + 3
Let's solve for x.
To solve for x, apply the altitude formula:

Where BD is the altitude.
Cross multiply:

Plug in the values and solve for x:

Take the square root of both sides:

Therefore, the value of x is 6 .
ANSWER:
d. 6
For 1 play, the chance of gaining $8 is 4/38, while the chance of losing the $1 is 34/38. Therefore, the expected value is ($8)(4/38) + ($-1)(34/38) = $(-1/19). Over 50 plays, which are mutually independent of each other, we multiply the number of plays by the expected value to get $(-50/19) = $-2.63.
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