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Math riddle? Answered

My friend asked me this one, I couldn't figure it out but I think the question itself is somehow flawed.Anyway, so here it goes:

A kid has to buy a toy of 100 Rupees, he takes Rs.50 from his father and 50 from his mother. Later when he goes to the store he finds that the toy is only 97 rupees, he buys the toy and 3 rupees are left, still with me? Now he goes to his mother and father and out of those 3 rupees gives one rupee to his father, one rupee to his mother and keeps the remaining 1 rupee aside (not for himself).

Now here is the question, as he has already given 1 rupee to his mother and father each, he has remaining 49 rupees to pay each one, so, my friend asks that add 49 to 49, 98, and then add to it the remaining 1 rupee he had kept aside, 99. Where did the remaining 1 rupee go?

I just can't understand what is he trying to ask, the calculation he just did, I think, has nothing to do with amount the kid has to pay or paid.



Best Answer 6 years ago

I've read a similar riddle with 3 guys paying a bill at a restaurant. The point of the riddle is that you add up positives and negatives as if they are all the same and end up with the wrong number.

Let us see it from the kid's point of view:
+ 50 (from father)
+ 50 (from mother)
- 97 (for toy)
- 1 (father)
- 1 (mother)
total: 1 rupee he kept aside.

What the riddle is trying to do is:
+ 49 (50-1 from father)
+ 49 (50-1 from mother)
+ 1 he kept
As you can see two of the three loose rupees are considered negative but one is considered positive. This is where the riddle tries to trick you. If you had consider all three rupees negative you end up with 97, which is what the toy really costs.


3 years ago

Lets solve this riddle in reverse direction...

You kept 1$. It means you have to 99$, and you bought the shirt for 97$ it means you have left with 2$ (and from those 2$ you returned 1$ to your mother and 1$ to your father).



5 years ago

I have no idea. If it's a riddle it probably has nothing to do with the math.


6 years ago

You can do something similar with just your fingers. (I assume you have 10 and are not missing one)
Start on one hand and count down, 10,9,8,7,6 then go to the other hand and count back up, 7,8,9,10,11 so suddenly you have 11 fingers.