-Logic question- Can someone help me with the math question?
Find the mistakes in the proof for the statement ”The sum of any two rational numbersis a rational number”.
Proof. Let rational numbers r=1/4 and s=1/2 be given. Then r+s=1/4+1/2=3/4. This is what was to be shown.

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

Agraphic designer created a logo on eight and a half by 11 inch paper. in order to be placed on a business card, the logo needs to be one and 7/10 inches by 2 and 1/5 in. what is the scale factor of the dilation

Is the power produced directly proportional to the wind speed, give reasons for your answer?