I wonder if they do this on purpose?

[plonq]

This Mensa calendar seems to have one bad page per month.  I enjoy the little brain exercises every day, but ones like this drive me up the wall:

Eight chocolate bars plus six gumdrops cost 70¢.  You could buy seven gumdrops for the price of two chocolate bars.  How much change will you get back from $1.00 if you buy six of each?


The answer is: What fucking planet do these guys come from?  Let's just check their math.

8c + 6g = 70¢
7g = 2c ... 3.5g = c

Okay, now let's substitute.

8(3.5g) + 6g = 70¢ ... 28g + 6g = 70¢ ... 34g = 70¢

Unless I've done something wrong, 34 gumdrops cost 70¢

That means one gumdrop = 2.0588235294117647058823529411765¢

But hang on...

7g = 2c ... g = 2/7c
8c + 6(2/7c) = 70¢ ... 8c + 12/7c = 70¢ ... 68/7c = 70¢ ... 68c = $4.90

Therefore a chocolate bar costs 7.2058823529411764705882352941176¢

If you bought 6 gumdrops and 6 chocolate bars you would get 44.411764705882352941176470588242¢ back in change.

Their expected answer:

ANSWER: 46¢ (A chocolate bar costs 7¢; a gumdrop costs 2¢.)

Hmph.  They didn't say anything about rounding to the nearest cent in the original problem.

Comments

[shiny-puppy.livejournal.com]

Wow, that was kind of fun. I got the right answer and didn't hesitate about rounding up to the next penny. I work in retail, you always round up. I managed to do all the division and such right, but made 12+42=46. Addition defeats me.