Answer: It will take 
of an hour to complete the test.
Step-by-step explanation:
We need to convert the mixed number 
to an improper fraction:
Now, we need to make the following add the fractions in order to calculate how many hours will it take to complete the test. Then, we get:
Therefore, it will take of an hour to complete the test.
4a-8=28
add 8 to both sides to start to isolate the variable (a)
-8+8 cancels each other out
28+8=36
4a=36
to completely isolate the variable divide both sides by 4
4a÷4=a
36÷4=9
a=9
Answer:
What is it rounded up to???
Step-by-step explanation:
I don't know what the "six-step method" is, but I do know how to solve the problem:
Let x = number of gallons of 50% solution
amount of antifreeze in 50% solution = 0.50x
amount of antifreeze in 10% solution = 0.10(80) = 8
amount of 40% solution = 0.40(x+80) = 0.40x + 32
Then, 0.50x + 8 = 0.40x + 32
0.10x = 24
x = 240 gal
