Ira bought a t-shirt that was discounted 50%. He used a coupon for 50% off at the cash register. Why was he charged $6.50 instead of $0?

50% off makes the new price half of the original, then another 50 % would be half off the discounted price, so they actually end up paying 25 % of the original price:

50 % x 50 % = 25 %

b.-4 units

all you   do is count how many times you move

no association

step-by-step explanation:

if you have eyes and you can use them efficiently you can see that it just looks like random dots like do a line of best fit and like they're so spread out it's such a weak association you might as well consider it nonexistent