Perimeter = 2 length + 2 width
P = 2(l) + 2(11/4)
(subtract 22/4 from each side)
(divide each side by 2)
7.5 ÷ 2 = l
3.75 = l
The answer is 3.75 or
P = 2(l) + 2(11/4)
7.5 ÷ 2 = l
3.75 = l
The answer is 3.75 or
A certain brand of electric bulbs has an average life of 300 hours with a standard deviation of 45. A random sample of 100 bulbs
2 answers:
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Expected Mean, E(X), is obtained by multiplying each pair of 
and its 
and add up the answers
E(X) = (0×0.7) + (1×0.2) + (2×0.1) = 0.4
The formula to calculate the variance, Var(X), is given by E(X)² - (E(X))²
E(X²) = (0²×0.7) + (1²×0.2) + (2²×0.1) = 0+0.2+0.4 = 0.6
(E(X))² = (0.4)² = 0.16
Var(X) = 0.6 - 0.16 = 0.44
Translating these answers into the context we have
E(Y) = 0.4×500 = $200
Var(Y) = $110
E(X) = (0×0.7) + (1×0.2) + (2×0.1) = 0.4
The formula to calculate the variance, Var(X), is given by E(X)² - (E(X))²
E(X²) = (0²×0.7) + (1²×0.2) + (2²×0.1) = 0+0.2+0.4 = 0.6
(E(X))² = (0.4)² = 0.16
Var(X) = 0.6 - 0.16 = 0.44
Translating these answers into the context we have
E(Y) = 0.4×500 = $200
Var(Y) = $110