Answer: 12 blue marbles
Step-by-step explanation: Set up a proportion.
4/5 = x/15
Solve for x, the number of blue marbles. Cross multiply. You will get 60 = 5x
Divide by 5 on each side.
x = 12
There are 12 blue marbles.
The answer is: 90° .
______________________________________________________
The 90% confidence interval is (70 - 4, 70 + 4). The margin of error is 4%.
The difference in gallons per day used is 3.6.
The formula to calculate a z-score is:

,
where X is the value used to calculate the score, μ is the mean and σ is the standard deviation. We have the z-scores so we must work backward:

For both equations, we will cancel the 1.2 by multiplying both sides:

Now we will cancel 2.2 from both equations by adding it to both sides:
3.6+2.2=X-2.2+2.2 and 0+2.2=X-2.2+2.2
5.8=X and 2.2=X
The difference in gas used per day would be given by
5.8-2.2 = 3.6.
The exponential parent function is D