First, you would multiply $210 by 20%
This is done by converting 20% to a decimal, .2
So, 210 • .2 = 42
Then to find the sale price, you would subtract that 42 that you just got from 210,
and you get $168 as the final sale price.
The question is a scientific inquiry. The explanation does not fit any of the four.

speed equals 825 divided by 17
speed equals to 48.5miles per hour
gas mileage equals to 825/38
gas mileage equals to 21.7
125/38 equals to 3.3 unit price
The perimeter would be rational due to both the width and length being rational numbers. A rational number is a number that can be written as a fraction such as 8 it can be written as 8/1, but a irrational would be a decimal number which in this case there would be none because both length and width is rational number. For example, Lets say the width is 8 and the length is 10. once both are written into fraction form such as 8/1 and 10/1 we add them to get a perimeter of 18.
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