Please identify the error 8 - (-2) = -8 +2 = -6
1 answer:
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Answer:
The mathematical expectation of a student who purchases 10 tickets is -$39.65.
Step-by-step explanation:
A student that purchases 10 tickets out of 2900 has a probability of winning the cruise that can be calculated as:
Each ticket cost $5, so he has spent $50 for the 10 tickets.
Then, the expected value of this operation is equal to the expected value of the earnings (probability of winning the prize multiplied by the value of the prize), minus the costs:
The mathematical expectation of a student who purchases 10 tickets is -$39.65.
Answer:
Fred C. 16.30 ft
Gary B. 169.67 m
Step-by-step explanation:
Fred the owl...
Always <u>draw a diagram first</u> (see diagram below). We assume trees are perpendicular (at 90°) to the ground. The situation forms a right-angle triangle.
We need to <u>find "x"</u>, which is the direct distance between the owl and the bird. "x" is also the hypotenuse, which is the longest side in a right-angle triangle. Since we know a side and an angle, we can find the hypotenuse using primary trigonometry ratios.
∠B will be the angle of reference (the angle we are "talking" about). The side we know is opposite to ∠B (15ft). We know it's opposite because it's not touching the angle. The side we need to find is the hypotenuse.
<u>Use the trig. ratio sine</u> because it has opposite and hypotenuse in it. The general formula is:
sinθ = opp/hyp
θ means the angle, and we know it is 67°.
Replace all the information you know:
sinB = opp/hyp
sin67° = (15ft) / x Isolate "x". Rearrange the equation.
xsin67° = (15ft) Divide both sides by sin67°
x = (15ft) / sin67°
x = 16.295... ft Exact answer in decimals
x ≈ 16.30 ft Rounded to nearest hundredth
Therefore Fred the owl is 16.30 feet from the bird.
Gary spots a monkey...
Draw a diagram first (see below). G is Gary, M is the monkey, T is the bottom of the Sears Tower. We need to <u>find "x"</u>, which is the distance between the monkey and the bottom of the tower.
The angle of reference is M, which is 69°. We need to find the adjacent side and we know the opposite side. <u>The trig. ratio that has adjacent and opposite is tangent.</u>
tanθ = opp/adj
Replace all the information you know:
tanM = opp/adj
tan69° = (442m) / x Rearrange the formula to isolate "x"
xtan69° = 442m Divide both sides by tan69°
x = 442m / tan69° Solve by dividing
x = 169.6679.... m Exact decimal answer
x ≈ 169.67m Rounded to the nearest hundredth
Therefore the monkey is 169.67 metres from the tower.
Remember all the trig. ratios using the acronym SohCahToa.
o = opposite side
a = adjacent side
h = hypotenuse side
S = sine, sin for short
C = cosine, cos for short
T = tangent, tan for short
The operation is always dividing the first side in the acronym by the second side.
sinθ = opp/hyp
cosθ = adj/hyp
tanθ = opp/adj
