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.
Answer:
90 hours
Step-by-step explanation:
The rate at which water enters the pool is
75 gallons
-------------------
1 hour
This is equivalent to
1 hour per 75 gallons, leading to:
1 hour
-------------------- * 6,750 gallons = 90 hours
75 gallons
Answer:
43.6 * 2.94 = 436/10 * 294/100 = (436 * 294)/1000 = 128184/1000 = 128.184
That's the simplest it can go.
Answer:
$162
Step-by-step explanation:
Discount = percentage discount ÷ 100 × original cost
Discount =
× $405 = $162