A store pays $13 for a bicycle helmet and marks up the price by 40% what is the amount of the mark-up?

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Jacob is graphing the line represented by the equation  −6x−5y=12.−6x−5y=12.  he first plots the  x-x-  and  y-interceptsy-intercepts  as follows.    which statement is correct regarding the intercepts on the graph?

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above