Let w bet the number of white cars and y the numbers of yellow cars.
"Rafael counted a total of 40 white and yellow cars" So w+y = 40.
"There were 9 times as many white cars as yellow cars" So 9Y = W
We get the system:
w+y=40 (1)
9y=w (2)
In equation (1), let's replace w by it's value from equation (2) since w=9y.
We get: 9y+y = 40
10y=40
y=4
So there's 4 yellow cars.
In equation (1), let's replace y by it's value
w+4=40
w=40-4
w=36
Rafael counted 36 white cars.
You can re-check your answer:
4+36=40 (w+y=40)
9*4=36 (9y=w)
The answer has been approved.
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Answer and explanation:
Please find attached answer and explanation
9514 1404 393
Answer:
34.6 ft
Step-by-step explanation:
The distance can be found using the Pythagorean theorem. Where a, b, c are the sides of a right triangle with c as the hypotenuse, it tells you ...
a² + b² = c²
a = √(c² -b²)
base-to-string = √(39² -18²) = √1197 ≈ 34.598
The distance from the base of the pole to the end of the string is about 34.6 feet.
Given:
n = 20, sample size
xbar = 17.5, sample mean
s = 3.8, sample standard deiation
99% confidence interval
The degrees of freedom is
df = n-1 = 19
We do not know the population standard deviation, so we should determine t* that corresponds to df = 19.
From a one-tailed distribution, 99% CI means using a p-value of 0.005.
Obtain
t* = 2.8609.
The 99% confidence interval is
xbar +/- t*(s/√n)
t*(s/√n) = 2.8609*(3.8/√20) = 2.4309
The 99% confidence interval is
(17.5 - 2.4309, 17.5 + 2.4309) = (15.069, 19.931)
Answer: The 99% confidence interval is (15.07, 19.93)
Answer:
x = 45
Step-by-step explanation:
Re-order terms so constants are on the left
15 * x/9 - 42 =28
Combine multiplied terms into a single fraction
15x/9 - 42 = 28
Cancel terms that are in both the numerator and denominator
5x/3 - 42 = 28