9514 1404 393
Answer:
78.5 km
Step-by-step explanation:
Measured at the airport, the angle between the two planes is ...
180° -60° -50° = 70°
The law of cosines tells us the distance between the planes is ...
d = √(50² +80² -2·50·80·cos(70°)) ≈ √6163.84 ≈ 78.5 . . . km
The planes are about 78.5 km apart.
Answer:
(6 , -1)
Step-by-step explanation:
2x+ y = 11 ----------------(I)
y = 11 - 2x --------------------(II)
Multiply the whole equation by 2
x - 10y = 16 --------------------(III)
Substitute y = 11- 2x in equation (III)
x - 10(11 - 2x) = 16
x - 110 + 20x = 16
21x - 110 = 16
21x = 16 +110
21x = 126
x = 126/21
x = 6
Plugin x = 6 in equation (II)
y = 11 - 2*6
y = 11 - 12
y = -1
Answer:
Step-by-step explanation:
its a
can i get brainliest ma'ma?
Answer:
99% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is [$(-31.82) , $12.02].
Step-by-step explanation:
We are given that a random sample of 16 sales receipts for mail-order sales results in a mean sale amount of $74.50 with a standard deviation of $17.25.
A random sample of 9 sales receipts for internet sales results in a mean sale amount of $84.40 with a standard deviation of $21.25.
The pivotal quantity that will be used for constructing 99% confidence interval for true mean difference is given by;
P.Q. = ~
where, = sample mean for mail-order sales = $74.50
= sample mean for internet sales = $84.40
= sample standard deviation for mail-order purchases = $17.25
= sample standard deviation for internet purchases = $21.25
= sample of sales receipts for mail-order purchases = 16
= sample of sales receipts for internet purchases = 9
Also, =
= 18.74
The true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is represented by ().
Now, 99% confidence interval for () is given by;
=
Here, the critical value of t at 0.5% level of significance and 23 degrees of freedom is given as 2.807.
=
= [$-31.82 , $12.02]
Hence, 99% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases is [$(-31.82) , $12.02].