Answer:
x = 15
Step-by-step explanation:
There are 2 triangles. The small triangle CDE has sides that are 8 and 20.
The big triangle CAB has sides 6+8 and 20 + x. Add the 6 and 8 which is 14. Create a proportion and cross multiply, divide, then solve for x.
Answer: The average was 9 years old find the average age of both groups is 10 years old.
Step-by-step explanation:
Formula foe average :
Given : The first group of students consists of 10 and their average age was 13 years old.
i.e. (1)
The next group consisted of 30 students and their average was 9 years old.
i.e. (2)
Then from (1) and (2) , the sum of both groups (first group and next group )students = 130+270 =400
Combined students of both groups (first and next group )= 10+30=40
Now , the average of both groups =
Hence, the average was 9 years old find the average age of both groups is 10 years old.
Answer:
Step-by-step explanation:
We know that:
In a deck of 52 cards there are 4 aces.
Therefore the probability of obtaining an ace is:
P (x) = 4/52
The probability of not getting an ace is:
P ('x) = 1-4 / 52
P ('x) = 48/52
In this problem the number of aces obtained when extracting cards from the deck is a discrete random variable.
For a discrete random variable V, the expected value is defined as:
Where V is the value that the random variable can take and P (V) is the probability that it takes that value.
We have the following equation for the expected value:
In this problem the variable V can take the value V = 9 if an ace of the deck is obtained, with probability of 4/52, and can take the value V = -1 if an ace of the deck is not obtained, with a probability of 48 / 52
Therefore, expected value for V, the number of points obtained in the game is:
So: