100% - 20% = 80%
$26.95 * 80% = $21.56
You multiply by 80% because you are taking 20% off and now want to know what 80% of the price will be.
18 x 4 = 72
(9 x 2) x 4 = 72
9 x (2 x 4) = 72
M/k=x
(m)m/k=x(m)
k=xm
Because you are diving one the side where m/k, you need to multiply m to both sides to get rid of it on one. Therefore, you are left with K=XM
I belive it is the second option!
