Answer: The mathematical expectation of Option A is 2.25. The mathematical expectation of Option B is 2.75. Option B offers a greater likelihood of advancing to the finish line.
Step-by-step explanation: I took the test.
Answer:
...what?
Step-by-step explanation:
≥≧≦≤
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<em>aM gObLiN gImMiE yE pOiNtS! </em> ( thanks )
So let's start from the beginning.
Add 2 and 4:
(2 + 4)
Multiply the sum by 3:
3(2 + 4)
Then add 5 to that product:
3(2 + 4) + 5
Then double the results:
2[3(2 + 4) + 5]
We'll use the following properties of sine and cosine to prove this:



Then it's just a matter of filling it in...
sin20sin40 * sin60sin80 = 1/2(cos20 - cos60) * 1/2 (cos20 - cos140) =
1/8( cos40 + 1 - cos160 - cos120 - cos40 - cos80 + cos80 + cos200) =
1/8(1 - cos160 - cos120 + cos200) =
1/8(1 - cos160 - cos120 + cos160) =
1/8(1 - cos120 ) = 1/8( 1 + 1/2 ) = 3/16
25x^2 = 16
divide each side by 25
x^2 = 16/25
take the square root of each side
sqrt (x^2) = +- sqrt(16/25)
x = +- sqrt(16)/sqrt(25)
x = +- 4/5
x = 4/5, - 4/5