Answer: she scored 69 points on the second test.
Step-by-step explanation:
Let x represent the number of points that she scored in the first test.
Let y represent the number of points that she scored in the second test.
If her mean score was 75, it means that
(x + y)/2 = 75
x + y = 75 × 2
x + y = 150- - - - - - - - - 1
If she scored 12 points more on the first test than the second test, it means that
x = y + 12
Substituting x = y + 12 into equation 1, it becomes
y + 12 + y = 150
2y + 12 = 150
2y = 150 - 12
2y = 138
y = 138/2
y = 69
Answer:
9
Step-by-step explanation:
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Answer:
0.3898 = 38.98% probability that there will be 4 failures
Step-by-step explanation:
A sequence of Bernoulli trials forms the binomial probability distribution.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
Let the probability of success on a Bernoulli trial be 0.26.
This means that 
a. In five Bernoulli trials, what is the probability that there will be 4 failures?
Five trials means that 
4 failures, so 1 success, and we have to find P(X = 1).
0.3898 = 38.98% probability that there will be 4 failures