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Math Riddle
lomiller
Member Posts: 1,810
For some reason I was thinking of this old math riddle and decided to post it. Not sure if I told it properly though. Its old so don’t post if you’ve seen it before.
Three men are taking a trip and their car breaks down. The only hotel nearby is a rather expensive $300 a night resort. They reluctantly take the room and agree to split the cost 3 ways, $100 each. The next morning the maid advises them to double check the price, as the room should have only been $250. They ask the front desk and sure enough get a $50 refund, but $50 doesn’t split evenly so they decide to take $10 each and give a $20 tip to the maid.
Now…
3 * $90 + $20 for the tip to the maid only comes to $290, what happened to the other $10?
Comments
The math seems to add up to me...
3 x 100 in the evening = $300
300-50 discount in the morning = $250
3 guys x $10 each = $30
1 x $20 tip = $20
$250 Bill + $30 change + $20 tip = Original $300
Maybe I missed something, but why over complicate it when the math works.
*edit* Just so you know...you are no longer dividing 300 by 3 but the 250. 250/3 = 83.33 + 10 = 93.33 x 3 = 279.99 + $20.00 = $299.99 (uncle sam took the penny)
"It is easier to be cruel than wise. The road to wisdom is long and difficult... so most people just turn out to be assholes" Feng (Christopher Walken)
I think 8hammer8 was taking this a bit too seriously.
Yes, obviously the math adds up if you're reading it from the top down and do the figures once you have all the info, but read his actual question, which is the actual riddle part of the riddle.
Obviously, each person got $10 back, so instead of 3 * 100, it's 3 * 90, which equals $270. $270 + the maid's tip of $20 only equals $290, $10 shy of the full $300. Thus, "what happened to the other $10?"Spoiler: The equation in itself is misleading. They all PAID $100 each for the $300 room. They each got $10 back, and gave $20 to the maid. Thus, the equation should simply read 3 * 90 = $270, MINUS the $20 to the maid, which equals the $250 used for the room. This riddle is kind of like the "where did Moses build his ark?" riddles. The question in itself is the piece of information that you need to speculate about, not the facts he originally gives you. If you follow only those instructions, it seems like really simple (stupid?) math, and doesn't seem like a riddle at all (I'm looking at you, hammer!).
_____________________________________
"Io rido, e rider mio non passa dentro;
Io ardo, e l'arsion mia non par di fore."
-Machiavelli
Spoiler: The equation in itself is misleading. They all PAID $100 each for the $300 room. They each got $10 back, and gave $20 to the maid. Thus, the equation should simply read 3 * 90 = $270, MINUS the $20 to the maid, which equals the $250 used for the room. This riddle is kind of like the "where did Moses build his ark?" riddles. The question in itself is the piece of information that you need to speculate about, not the facts he originally gives you. If you follow only those instructions, it seems like really simple (stupid?) math, and doesn't seem like a riddle at all (I'm looking at you, hammer!).
Hey Hey Hey....I have to take it seriously because I seriously HATE math. I am not bad at it, it just annoys me to no end (stems from a mental block I put in as a child due to a teacher I had). So I figured if I came up with the answer I could kill it in 2 posts, a record even for me (as I think I am in the top 10% of thread ending posts here). Some people are trying to keep it alive with a bunch of smack talking ....I am looking at YOU ViolentY!!
"It is easier to be cruel than wise. The road to wisdom is long and difficult... so most people just turn out to be assholes" Feng (Christopher Walken)
One of my old favorites, I've forgotten the terms probably, but it is still fun:
a = b + c, where c > 0, therefore a != b.... an axiom or something like that.
a = b + c
a(a - b) = b(a - b) + c(a - b) multply both sides by (a - b)
aa - ab = ba - bb + ac - bc I forget what this is called:) "Do the multiplication" lol
aa - ab - ac = ba - bb - bc subtract ac from both sides
a(a - b - c) = b(a - b - c) factor out (a - b -c) from both sides
a = b divide both sides by (a - b - c)
a(a - b) = b(a - b) + c(a - b) multply both sides by (a - b)
since a - b = c what you are really doing is multplying by c to get
ac = c(b+c)
subtracting ac from both sides therefore gives you
0 = c(b + c) -ac which can be rewritten as
0 = c(b + c - a) but (b + c - a) also = 0
IOW both sides of the equation have been reduced to 0 at the point where you subtract ac
a(a - b - c) = b(a - b - c) factor out (a - b -c) from both sides
a - b - c = 0, so you can't do this.