Answer:
813 N/m²
Step-by-step explanation:
The units of pressure tell you it is found by dividing force by area. Here, we need to convert the units of the given area so we can express the pressure appropriately.
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pressure = force / area
pressure = (61 N)/(750 cm² × ((1 m)/(100 cm))²) = (61 N)/(0.0750 m²)
pressure ≈ 813 N/m²
Let's say we'll mix "x" amount of the 80% solution, how much antifreeze is in it? well is just 80% of antifreeze, and the rest is something else.... what's 80% of "x"? so is (80/100)*x, or 0.8x.
likewise, the mixture will be a 70% solution, and let's say it adds up to "y" amount, so how much antifreeze is in it? well (70/100) * y or 0.7y.

so whatever "x" is, we know that
x + 100 = y.
and we know that
0.8x + 10 = 0.7y.
I believe that is ten right?
Hey there! I'm happy to help!
A mixed number is a whole number and a fraction. We already see that our whole number is 7.
Our decimal is 0.13. Since this goes into the hundredths place, we can rewrite this as 13/100. This cannot be simplified anymore.
Therefore, 7.13 is 7 13/100 in lowest terms.
Have a wonderful day! :D