Had by an ad?

A hamburger chain advertises that its 1/2-pound hamburgers are 50% bigger than its competitor's 1/3-pound hamburgers. Is this false advertising? [From CCTT writing institute, 6/01]


50%(or 1/2) of 1/3 pound is 1/6 pound. 1/6 pound more than 1/3 pound is 1/2 pound. So it's not false advertising.

What's wrong with these other approaches, which claim the opposite?

50% (or 1/2) of 1/2 is 1/4. 1/2 - 1/4 = 1/4, which is less than 1/3. So 1/2 is more than 50% more than 1/3, and it is false advertising.

If one number is 50% more than the other, is the other 50% less than the one?

50% (or 1/2) of 1/3 is 1/6. 1/6 is not nearly so big as 50%, or 1/2. So the 1/2-pound hamburger is not nearly 50% bigger than the 1/3-pound hamburger. It is false advertising.

Why are you using 50% in two different ways?

Your experience

Have you used this problem with a class and seen approaches other than(or more specific than) those mentioned above? Or do you have other comments or criticisms or stories? If so, please tell us!

Last updated 30 November, 2004