Answer:
4x+x=40
5x+40
x=8
8, 32
Step-by-step explanation:
I will give you everything I can do:
11)
Lets say Car A travels at x mph. That means Car B travels at x+2 mph.
Both of them are traveling towards each others, so we can say the total speed is 2x+2.
Now i takes 3 hrs and we know the distance.
Since R*T=D
Then 3(2x+2)=270
So 2x+2=90
2x=88
x=44
12)
To find perpendicular we want to find the opposite reciprocal of the original slope. Therefore the slope is 3/2.
Now we must find the equation of the line with the given variable.
First find b.
5=3/2*4+b
b = -1
So the equation of this line is:
y=3/2x-1
13) All work will be shown below.
6-3(-2-4x)=2(3(x-4)+7)
6+6+12x=2(3x-12+7)
12+12x=2(3x-5)
12+12x=6x-10
6x=-2
x = -1/3
14)
First we must find the amount each train traveled.
The speed of F train(Freight train)=x
The speed of P train(passenger train)=x+6
Their combined speed is 2x+6
It takes 2 hrs to cover 100 miles
So 2(2x+6)=100
2x+6=50
2x=44
x=22
So the freight train covered 44 miles and the passenger train covered 56 miles.
To find average speed you must do Total Distance/Total Time.
44/2 and 56/2
Which are 22 and 28.
The average speed of F train is 22 mph and average speed of P train is 28 mph.
15) Again opposite reciprocal.
3/5 -> -5/3
Work:
-4=-3*-5/3+b
-4=5+b
b=-9
y = -5/3x-9
16)
F=kx-kx0
First kx0 = 0
So F=kx
So x=F/k
Answer:
11
Step-by-step explanation:
W^7/W^-2=W^7+2=W^9 ( when divide subtract the exponent (7-(-2))
W^?/W² = W^?-2
W^9=W^(?-2)
9=?-2
?=11
W^7/W^-2 = W^11/W²
23/10 = 2 and 3/10
I hope this helped
Answer: 16%
Step-by-step explanation:
When we have a normal distribution, the 100% of our sample will be placed in a "gaussian bell".
Where the middle of this bell coincides with the mean.
The mean, in this case, is 1200, and the standard deviation is 200.
In the image below you can see that between the points.
Mean + standard deviation and the end of the graph, we have:
13.5% + 2.35% + 0.15% = 16%
And particularly, if we want to know the percentage that exceed 1400, will be the same percentage above the mean plus the standard deviation.
mean = 1200
SD = 200
mean + standard deviation = 1200 + 200 = 1400.
Then the percentage that exceeds 1400 is equal to the percentage that we found above, then the correct option is C: 16%