Eric has a riddle: "I am thinking of a fraction that is equivalent to
1 answer:
Answer:
This is the same as writing 12/30
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Explanation:
d = value of the denominator
d-18 = value of the numerator, since it's 18 less than the denominator
The fraction Eric is thinking of is where d cannot be zero. This fraction is equivalent to
so we'll set the two fractions equal to one another and solve for d.
The denominator is d = 30 and the numerator is d-18 = 30-18 = 12.
The unreduced fraction Eric is thinking of is .
To verify the answer, notice that:
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Answer:
probability that all the 15 students selected are girls
Step-by-step explanation:
The selection is from a sample without replacement, so we use the hypergeometric distribution to solve this question.
Hypergeometric distribution:
The probability of x sucesses is given by the following formula:
In which:
x is the number of sucesses.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
All girls from the first group:
20 students, so
10 girls, so
5 students will be selected, so
We want all of them to be girls, so we find P(X = 5).
All girls from the second group:
20 students, so
5 girls, so
5 students will be selected, so
We want all of them to be girls, so we find P(X = 5).
All girls from the third group:
20 students, so
8 girls, so
5 students will be selected, so
We want all of them to be girls, so we find P(X = 5).
All 15 students are girls:
Groups are independent, so we multiply the probabilities:
probability that all the 15 students selected are girls
Answer:
Y=2/5x-2
Explanation:
Y=2/5x-2
Explanation: