Answer:
There are 12 red fish, 19 orange fish
Step-by-step explanation:
Let y rep amount of red fish
y + 7 = Amount of orange fish
y + y + 7 = 31
2y = 31 - 7
2y = 24
y = 12
Then
y + 7
12 + 7 = 19
Answer:
D
Step-by-step explanation:
This comes out to 4. The other ones are absolute value, meaning there are no negatives. You can think of subtracting as adding a negative. When you role a dice however, you are never really moving backward.
Answer:
The probability of picking a purple marble, and then, not replacing picking an orange marble is approximately 20%
Step-by-step explanation:
First we know that there are 20 marbles in the bag, so the probability of picking a purple marble is 11/20. If we take a purple marble out, there will only be 19 marbles remaining in the bag. So the probability of picking an orange marble would be 7/19. Now, all we need to do is multiply the 2 fractions, and we will get 77/380 which equals to which is approximately 20% .
Answer:
The 99% confidence interval for the mean number of computer games purchased each year is between 7.3 and 7.5 games.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 7.4 - 0.1 = 7.3.
The upper end of the interval is the sample mean added to M. So it is 7.4 + 0.1 = 7.5
The 99% confidence interval for the mean number of computer games purchased each year is between 7.3 and 7.5 games.