Answer: (30.49 years, 42.31 years)
Step-by-step explanation:
The formula to find the confidence interval is given by :-

, where
= Sample mean
z* = Critical value.
= Population standard deviation.
n= Sample size.
As per given , we have
n= 40
We know that the critical value for 99% confidence interval : z* = 2.576 (By z-table)
A 99 percent confidence interval for µ, the true mean age of guests will be :

∴ a 99 percent confidence interval for µ, the true mean age of guests = (30.49 years, 42.31 years)
Let's let the weight of a large box be L, and the weight of a small box be S.
We know that 5 large boxes and 3 small boxes is 120kg, so:
5L + 3S = 120
We also know that 7 large boxes and 9 small boxes is 234kg, so:
7L + 9S = 234
You can multiply the first equation by 3 to get:
15L + 9S = 360
See how now both equations have 9S? We can now subtract one from the other:
(15L+9S) - (7L+9S) = 360-234
8L = 126
L = 15.75
Now sub this value back into an equation:
(5x15.75) + 3S = 120
3S = 41.25
S = 13.75
Double check these values
(7x15.75) + (9x13.75)
= 110.25 + 123.75
=234, which is consistent with above.
So a large box is 15.75kg, and a small box is 13.75kg.
Hope this helped
Answer:
x and y do not show direct variation.
Step-by-step explanation:
The formula for direct variation is
y = kx Divide each side by y
k = y/x
k should have the same value for every point except, of course, (0,0)
For the first point,
k = 2/(-1) = -2
For the third point,
k = 2/1 = 2
The values of k are different, so x and y <em>do not</em> show direct variation.
Replace the f(x) in the second equation will 6x + 5 so then it looks like 2(6x + 5) + 6. Then distribute so it’s 12x + 10 + 6 and then simplify to 12x + 16