Answer:
7
Step-by-step explanation:
hi , you can see here we have a rectangle without a triangle :
area rectangle - area triangle = area of the shape
Area of the triangle= L x l
=4 x 2
=8
Area of the triangle =
=
=1
So we do : 8 - 1 = 7
I hope it is gonna be helpful,
have a nice day.
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