So for 6, store A would be cheaper. Here's why. 10% of 35 is 3.5, so times 3.5 by 2 and you get 7, subtract 7 from 35 and you get 28. Now to store B. 10% of 45 is 4.5, times that by 3 and you get 13.5, 45-13.5 is 31.5. So which is cheaper? 28 or 31.5? That's your answer.
