Acertain diet program promises that a 200 pound person can lose 6 pounds per week using their product

I don't think that's true just using the diet alone wouldn't promise any thing more than just more weight. you DO need to eat healthy but also exercise on a daily basis.

On monday,mrs.wise bought 3 lbs of apples at $4per lb= 4*3=$12on tuesday ,20%off and she buy 5 lbs of apples = $4-20%=3.20*5lb=$16example: other wise when she buy 5lbs on monday she have to spend 4*5=20