The period of a sinusoid

is

, so any range such that

will give two complete periods.
Answer:
The probability that all will last at least 30,000 miles is 0.3164.
Step-by-step explanation:
Consider the provided information.
For a particular tire brand, the probability of wearing out before 30,000 miles is 0.25. Someone who buys a set of four of these tires,
That means the probability of not wearing out is 1-0.25 = 0.75
Now use the binomial distribution formula.

Substitute p = 0.25, q=0.75, r=4 and n=4



The probability that all will last at least 30,000 miles is 0.3164.
Answer:
Proved,
P(A∪B)=0.72
Step-by-step explanation:
Sue travels by bus or walks when she visits the shops.
Probability( catch the bus to the shop ), P(A) = 0.4
Probability( catch the bus from the shop ), P(B) = 0.7
Both A and B are independent events.
Therefore,
P(A∩B) = 0.4×0.7
= 0.28
Probability Sue walks one way = 1 - P(A∩B)
= 1 - 0.28
= 0.72
Hence, the probability that Sue walks at one way is 0.72