Have a few points answer quick

Which representation has a constant of variation of -2.5

An unknown number x is at most 10. which graph best represents all the values of x? number line graph with closed circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the left. number line graph with closed circle on 10 and shading to the left.

Can someone me find the original price? the discount is 5% and the sale price is $68.40