Answer:
(a) E(X) = -2p² + 2p + 2; d²/dp² E(X) at p = 1/2 is less than 0
(b) 6p⁴ - 12p³ + 3p² + 3p + 3; d²/dp² E(X) at p = 1/2 is less than 0
Step-by-step explanation:
(a) when i = 2, the expected number of played games will be:
E(X) = 2[p² + (1-p)²] + 3[2p² (1-p) + 2p(1-p)²] = 2[p²+1-2p+p²] + 3[2p²-2p³+2p(1-2p+p²)] = 2[2p²-2p+1] + 3[2p² - 2p³+2p-4p²+2p³] =  4p²-4p+2-6p²+6p = -2p²+2p+2.
If p = 1/2, then:
d²/dp² E(X) = d/dp (-4p + 2) = -4 which is less than 0. Therefore, the E(X) is maximized.
(b) when i = 3;
E(X) = 3[p³ + (1-p)³] + 4[3p³(1-p) + 3p(1-p)³] + 5[6p³(1-p)² + 6p²(1-p)³]
Simplification and rearrangement lead to:
E(X) = 6p⁴-12p³+3p²+3p+3
if p = 1/2, then:
d²/dp² E(X) at p = 1/2 = d/dp (24p³-36p²+6p+3) = 72p²-72p+6 = 72(1/2)² - 72(1/2) +6 = 18 - 36 +8 = -10
Therefore, E(X) is maximized.
 
        
             
        
        
        
Answer:
24.9
first to find the price of the DVD's you multiply 5 x 4.40 which is 22, then you add the 2.90 10 get 24.90. 
btw plz put me as brainliest. 
 
        
             
        
        
        
Answer: 125,000 BTUs
Step-by-step explanation:
Hi, to answer this question we have to apply proportions:
A fuel tank has a volume of 36 gallons. When filled with biodiesel, it provides 4,500,000 BTUs
So, the proportion is:
36 gallons / 4,500,000 BTUs
For 1 gallon  
1 gallon / x BTUs
36/4,500,000 = 1/x
Solving for x:
x = 1 / (36/4,500,000)
x = 125,000 BTUs
Feel free to ask for more if needed or if you did not understand something.
 
        
             
        
        
        
Answers:
1. V=triangle area × length
V=1/2×8×12×20
V=960in³
2. triangle area × length
Area of the triangle=1/2×4×11
A=22ft²
V=22×6
V=132ft³
3. b, volume always have cubic power (³)
4. d, same reason of question 3