Rs.80 means 80 rupees, right?  That's what Google and Wikipedia seem to think, but I'm not really familiar with Indian currency so I could easily be wrong.  I'm just going to write it out as "80 rupees" in the rest of this post, so if that's not proper notation, I apologize.

Mathematically, it's not a particularly difficult question.  If 80 rupees is the difference between gaining 10% and losing 10%, then 80 rupees is 20% of the selling price.  80 * 5 is 400 rupees, so the original cost price is 400 rupees.

I'm pretty sure I got that right...

I was one of 2 in my current Math class to get this one right.

Three travelers stopped at an inn for supper. The innkeeper could offer only baked potatoes. While the potatoes were baking, the weary travelers fell asleep. Soon, one of them woke up, saw the dish of potatoes and took a third of them without waking up the others. Later the second one woke up, saw the dish, and ate a third of the remaining potatoes. Later the third one did the same. When all three were sleeping once again, the innkeeper cleared the table and found 8 potatoes left. How many potatoes were originally on the table?

Quote from: Redz on October 05, 2009, 08:14:46 PM

I was one of 2 in my current Math class to get this one right.

Three travelers stopped at an inn for supper. The innkeeper could offer only baked potatoes. While the potatoes were baking, the weary travelers fell asleep. Soon, one of them woke up, saw the dish of potatoes and took a third of them without waking up the others. Later the second one woke up, saw the dish, and ate a third of the remaining potatoes. Later the third one did the same. When all three were sleeping once again, the innkeeper cleared the table and found 8 potatoes left. How many potatoes were originally on the table?

should be 27.

27 - 1/3 (9) = 18 - 1/3 (6) = 12 - 1/3 (4)= 8

yes sir

I was one of 2 in my current Math class to get this one right.

Three travelers stopped at an inn for supper. The innkeeper could offer only baked potatoes. While the potatoes were baking, the weary travelers fell asleep. Soon, one of them woke up, saw the dish of potatoes and took a third of them without waking up the others. Later the second one woke up, saw the dish, and ate a third of the remaining potatoes. Later the third one did the same. When all three were sleeping once again, the innkeeper cleared the table and found 8 potatoes left. How many potatoes were originally on the table?

18

edit - woops, thought there were only 2 people taking 1/3...haha, I actually started with 27 first, and did the 1/3, 1/3, in my head, but since I for some reason dont know how to read, realized that was too many.  But I would have had it on my first educated guess had I learned to read. lol

My class this weekend was very big into honoring students various methods of solving math problems (not being a stickler for one method like I when I was in school).

Let me know how you guys figured it out. 

Quote from: Redz on October 05, 2009, 08:14:46 PM

I was one of 2 in my current Math class to get this one right.

Three travelers stopped at an inn for supper. The innkeeper could offer only baked potatoes. While the potatoes were baking, the weary travelers fell asleep. Soon, one of them woke up, saw the dish of potatoes and took a third of them without waking up the others. Later the second one woke up, saw the dish, and ate a third of the remaining potatoes. Later the third one did the same. When all three were sleeping once again, the innkeeper cleared the table and found 8 potatoes left. How many potatoes were originally on the table?

should be 27.

27 - 1/3 (9) = 18 - 1/3 (6) = 12 - 1/3 (4)= 8

Yep, that's what I came up with, too.  It probably took me a little longer than it took you, though.

I always liked this one (From Die Hard 3).  Not too difficult at all, but fun

To stop a bomb going off, McClane and Zeus have to measure out exactly four gallons of water from a fountain using a three gallon jug and a five gallon jug.

So how do you do it?

Fill the five and pour it into the three.

That leaves 2 in the five gallon jug.

Dump out the three gallon jug and transfer the two gallons from the five to the three

Fill the five gallon jug and pour from it into the three gallon jug until it is full.

Four gallons remaining in the five gallon jug.