Answer:
it means d is less than 8.
Step-by-step explanation:
Answer:
0.0111% probability that he answers at least 10 questions correctly
Step-by-step explanation:
For each question, there are only two outcomes. Either it is answered correctly, or it is not. The probability of a question being answered correctly is independent from other questions. So we use the binomial probability distribution to solve this question.
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.
A multiple-choice examination has 15 questions, each with five answers, only one of which is correct.
This means that 
What is the probability that he answers at least 10 questions correctly?









0.0111% probability that he answers at least 10 questions correctly
It is 9
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Answer:
The plans will cost the same when the amount you have to pay for talking for "x" minutes on Plan A is the same has what you have to pay for talking for the same number of "x" minutes when using Plan B.
$$ Plan A = $$ Plan B
To find the charge on each plan we add the base rate to the per minute call rate for each.
Plan A = $27 + $0.11x
Plan B = $13 + $0.15x
Let's drop the $ sign for now and get rid of the decimal point by multiplying by 100.
2700 + 11x = 1300 + 15x
Subtracting 11x and 1300 from both sides:
4x = 1400
x = 350 min.
Using this result the plans both cost $65.50 for 350 min of talk time.
Step-by-step explanation:
boom :)