40 x 5280 = 211200 feet per hour
211200 / 3600 = 58.666 = 59 feet per second
Answer: A; 6.3%
Step-by-step explanation:
Problem 1
For the first problem, we first want to find y so that we can plug it into the expression.
We can use elimination method for the system of equations to solve.
3x+3y=21
3x-y=5
We subtract both equations to eliminate x.
4y=16 [divide both sides by 4]
y=4
Now that we know y, we can plug it into the expression.
[divide]
[subtract]

We know that the answer is A.
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Problem 2
For the second problem, we need to know how to calculate percent error. The formula for precent error is
. We know that the exact value is 80 because the buyer was supposed to given 80. 75 is the measured value because that was what the buyer was given.
[subtract]
[solve absolue value]
[divide]
[multiply]

Since the problem said to round to one decimal place, we know that the answer is 6.3%.
Answer:
0.00539218411
Step-by-step explanation:
-4x - 11 = 2(x - 3x) + 13
-4x - 11 = 2x - 6x + 13
-4x - 11 = -4x + 13
-4x + 4x = 13 + 11
0 = 24...incorrect......no solutions for this problem
Answer:
18
Step-by-step explanation:
30*0.4=12
This means 40% of 30 is 12 and Ana has completed 12 problems.
30-12 = 18, so she still needs to do 18 problems.