Answer:
90% of the questions she answered correctly
Step-by-step explanation:
%age = 81/90 * 100= 90 % correctness
Answer:
The probability that more than half of them have Type A blood in the sample of 8 randomly chosen donors is P(X>4)=0.1738.
Step-by-step explanation:
This can be modeled as a binomial random variable with n=8 and p=0.4.
The probability that k individuals in the sample have Type A blood can be calculated as:

Then, we can calculate the probability that more than 8/2=4 have Type A blood as:

Answer:

Step-by-step explanation:
we know that
The equation of a exponential decay function is given by

where
y is the value of the investment
x is the number of years
a is the initial value
r is the rate of change
we have

substitute


Find the amount Amy has at the end of 8 years
For x=8 years
substitute the value of x

She will need 12 seconds because -20•12=-240