A fountain on a lake sprays water in a parabolic arch modeled by the equation y = -0.3x2 + 3x. A beam of light modeled by the eq
uation -2x + 5.5y = 19.5 passes through the fountain to create a rainbow effect. If the beam cuts the water spray at points A and B, such that point B is at a higher level than point A, what distance from the ground level is point A?
1 answer:
See the attached figure.
Water model ⇒⇒⇒ y = -0.3 x² + 3x ( blue graph )
Light model ⇒⇒⇒ -2x + 5.5 y = 19.5 ( red graph )
The intersection between the two models A and B
A = ( 1.657 , 4.148 )
B = ( 7.13 , 6.138 )
<span>B is at a higher level than point A
</span>
<span>The distance from the ground level to point A = y-coordinate of point A
= 4.148
</span>
Water model ⇒⇒⇒ y = -0.3 x² + 3x ( blue graph )
Light model ⇒⇒⇒ -2x + 5.5 y = 19.5 ( red graph )
The intersection between the two models A and B
A = ( 1.657 , 4.148 )
B = ( 7.13 , 6.138 )
<span>B is at a higher level than point A
</span>
<span>The distance from the ground level to point A = y-coordinate of point A
= 4.148
</span>
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Answer:
Step-by-step explanation:
Suppose pieces of chocolate pie served at a restaurant average 350 calories with a standard deviation of 20 calories. Calories have a Normal distribution due to inexact cutting of the pies. Which graph represents the proportion of pieces of pie that have more than 375 calories.
Answer: The z score is used to determine how many standard deviations that the raw score is above or below the mean. If the z score is positive then the raw score is above the mean and for a negative z score means the raw score is below the mean. The z score is given as:
Given that: μ = 350 calories, σ = 20 calories, x > 375
From the graph, The shaded area represents the proportion of pieces of pie that have more than 375 calories
From the normal distribution table, P(x > 375) = P(z > 1.25) = 1 - P(z < 1.25)
= 1 - 0.8944 = 0.1056 = 10.56%
