We have been given for a normal distribution the mean time it takes to walk to the bus stop is 8 minutes with a standard deviation of 2 minutes. And the mean time it takes for the bus to get to school is 20 minutes with a standard deviation of 4 minutes.
(a) Average time that it would take reach school can be obtained by adding the average times.
8+20 = 28 minutes.
(b) Standard deviation of the trip to school can be found as:

Therefore, standard deviation of the entire trip is 4.47 minutes.
(c) Let us first find z score corresponding to 30 minutes.
We need to find the probability such that 
Therefore, the required probability is 0.67.
(d) If average time to walk to school is 10 minutes, then overall average time for the trip will be 10+20 = 30 minutes.
(e) Standard deviation won't change it will remain 4.47
(f) The new probability will be:


Therefore, probability will be 0.50.
Step-by-step explanation:
Since
varies directly as
we can write the relation as

where k is the constant of proportionality.
a) To solve for the k, we substitute the given values:


b) The equation relation x and y can be written as

c) When y = 9,

Answer:
-3072
Step-by-step explanation:
Answer:
120
Step-by-step explanation:
180-50-70=60
180-60=120
1. vertex is -4 because:
x^2-8x-20,
a=1, b=-8 , c=-20
use vertex form! -b/2a = -8/2(1) = -8/2 = -4.
2. axis of symmatry is the x which is also -4. The same steps go for the second one.
3. y intercept, I think the answer is -20. Im not sure for this one.
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