<h3>
Answer: </h3><h3>
speed of train A = 44 mph</h3>
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Work Shown:
x = speed of train A
y = speed of train B
"train A travels 4/5 the speed of train B" (I'm assuming "train one" is supposed to read "train B"). So this means x = (4/5)y
distance = rate*time
d = x*7
d = (4/5)y*7 = (28/5)y represents the distance train A travels
d = y*7 = 7y represents the distance train B travels
summing those distances will give us 693
(28/5)y + 7y = 693
5*( (28/5)y + 7y ) = 5*693
28y + 35y = 3465
63y = 3465
y = 3465/63
y = 55
Train B's speed is 55 mph
4/5 of that is (4/5)y = (4/5)*55 = 4*11 = 44 mph
Train A's speed is 44 mph
2x^2-4=124 is the correct answer.
Answer:
The player's height is 4.45 standard deviations above the mean.
Step-by-step explanation:
Z-score:
Measures how many standard deviations a measure X is above or below the mean.
His height converts to the z score of 4.45.
This means that:
The player's height is 4.45 standard deviations above the mean.
Answer:
Twenty-three thousand five hundred seventy-nine
Step-by-step explanation:
Answer:
Rate of change of the area of the square is 42 units at t = 2.
Step-by-step explanation:
We note that the area of the square is given by: 
but we aim to find 
. But we can use the chain rule to pull out that dA/dt. Doing so gives us:
Now, 
(by the power rule and 
But since we have "x" and not "t", we want to find what x is when t = 2. Substituting t = 2 gives us x(2) = 3(2) + 1 = 7.
So, finally, we see that:
