Answer:
-1.683
Step-by-step explanation:
Given :
Group 1 :
x1 = 667 ; n1 = 10 ; s1 = 20
Group 2 :
x2 = 679 ; n2 = 14 ; s2 = 15
The test statistic assuming equal variance :
x1 - x2 / √[Sp² * (1/n1 + 1/n2)]
sp² = [(n1 - 1)*s1² + (n2 - 1)*s2²] ÷ (n1 + n2 - 2)
Sp² = [(10 - 1)*20² + (14 - 1)*15²] = 296.59
Test statistic =
(667 - 679)/ √[296.59 * (1/10 + 1/14)]
-12 / 7.1304978
Test statistic = - 1.682
The two planes are flying on the two legs of a right triangle.
The straight distance between them is the hypotenuse of the triangle.
Since the speeds are in mph, let's work the time in hours.
Call the time 'H' that we're looking for.
It's the number of hours after they both take off that they're 650 miles apart.
After 'H' hours, the first plane has gone 500H miles north.
After 'H' hours, the second plane has gone 1200H miles east.
After 'H' hours, they are 650 miles apart.
Do you remember this for a right triangle ? ==> A² + B² = C²
(500H)² + (1200H)² = (650)²
250,000H² + 1,440,000H² = 422,500
1,690,000 H² = 422,500
H² = (422,500) / (1,690,000) = 0.25
H = √0.25 = 1/2 hour = 30 minutes
Answer:
5
Step-by-step explanation:
You need to set up and solve a system of linear equations here.
Let s and a represent the number of students and adults respectively.
Then s + a = 9, and s = 9 - a.
Total ticket cost for the adults was ($8/adult)(a)
and for the students ($5/student)(s).
Total cost of the tickets was then ($8/adult)(a) + ($5/student)(s) = $60.
Then our system of linear equations is:
8a + 5s = 60
a + s = 9, or s = 9 - a. Substituting 9 - a for s, we get:
8a + 5(9 - a) = 60.
Then 8a + 45 - 5a = 60, or 3a = 15.
Solving for a, we get a = 5.
Solving for s using s = 9 - a, we get s = 9 - 5, or s = 4.
There were 5 adults in the group (and 4 students).
Hi there!
The answer would be B. The number 3 was rolled 5 times in 36 trials.
This shows that out of all 36 times the dice was rolled the number 3 faced upwards 5 times.
Hope this helps !
In a 30 - 60 - 90 triangle the side opposite the hypotenuse is 1/2 the hypotenuse and which will be the shorter side. Read this over a couple of times till you realize that (x + 12)/2 is the shortest side.
[(x + 12) / 2]^2 + x^2 = (x + 12)^2 subtract [(x + 12)/2]^2 from both sides.
x^2 = (x +12)^2 - [ (x +12)/2]^2
x^2 = (x + 12)^2 [ 1 - (1/2)^2] You were given this as a question in school? It seems awfully hard.
x^2 = (x + 12)^2 [3/4]
4x^2 = 3*(x^2 + 24x + 144)
4x^2 = 3x^2 + 72x + 432
x^2 - 72x - 432 = 0 This is a quadratic, do you know what they are?
The solution to this comes to x = 77.56
I don't think I made a mistake, but it is sure possible.Check the numbers and my method.
