hmmm units rates are just a matter of one above the other.
in this case is points/week.
9/15 points/weeks, we can just divide 9 ÷ 15 = 0.6, or 3/5.
so 0.6 points/weeks.
To find the value of 
, we need to isolate it on one side of the equation. Add 
to both sides of the equation, then multiply both sides of the equation by 
.
Simple, finding markdown, use these two formulas.
Markdown=Original-New
and
Percent Markdown= Markdown Amount/Original*100
So,
Markdown=612-450
M=162
Markdown%= 162/612*100
M%=0.2647*100
M%=26.5 (rounded)
Thus, there was a 26.5% decrease.
