Because of cholesterol problems, I must take a certain medicine. Every week I buy a box, which lasts me for seven days.

However, things are not so bad. The laboratory that produces this medicine has an standing offer: for every five empty boxes, they give you a free new box.

Thus, I get six boxes paying just for five; it means a 16.67% savings for me... right or wrong?

Good news, it's wrong :).

After you returned the initial 5 boxes, you get 1 free box (now you have 1 box), you buy 4 more boxes and once again you have 5 empty boxes. You return those boxes and get a free one again. But in order to get this free box you only had to buy 4 boxes.

Therefore you get 5 boxes for the price of 4 (because the free box always counts towards your next 5 empty boxes), which means a saving of 20% for you.

Posted by Gregor on 2006-08-11 08:22:17