It’s either just 2xy or it’s 2xy(x+2)(x-4)
let's say the bill without the tip is "x" amount, so that'd be the 100% of the bill, but we also know that 4.50 is the 18% of "x".
so if 4.50 is the 18% of "x", how much is "x"?
Answer: There is sufficient evidence to reject the dealer's claim that the mean price is at least $20,500
Step-by-step explanation:
given that;
n = 14
mean Ж = 19,850
standard deviation S = 1,084
degree of freedom df = n - 1 = ( 14 -1 ) = 13
H₀ : ц ≥ 20,500
H₁ : ц < 20,500
Now the test statistics
t = (Ж - ц) / ( s/√n)
t = ( 19850 - 20500) / ( 1084/√14)
t = -2.244
we know that our degree of freedom df = 13
from the table, the area under the t-distribution of the left of (t=-2.244) and for (df=13) is 0.0215
so P = 0.0215
significance ∝ = 0.05
we can confidently say that since our p value is less than the significance level, we reject the null hypothesis ( H₀ : ц ≥ 20,500 )
There is sufficient evidence to reject the dealer's claim that the mean price is at least $20,500
Luckily for us, this problem solved the bulk of its own question!
Now, all we have to do is solve for "x", or the amount of fiction books and plug its value back into the original equation to find the value of "y", or the amount of nonfiction books.
2x = 38
x = 19
There are 19 fiction books.
x + y = 26
19 + y = 26
y = 7
There are 7 nonfiction books.
Hope this helps!
