The Poisonous Glass?

You are given 4 identical glasses, completely filled with transparent, odorless liquids. Three of the liquids are pure water, and the fourth is poison, which is slightly heavier. If the water glasses weigh 250 grams each, and the poisoned glass weighs 260 grams, how can you figure out which one is which, using a measuring scale just once?

Here is the process to identify the poisonous glass!

Identifying The Poisonous Glass!

What was the challenge?

Let's number the 4 glasses as 1,2,3 and 4.

Here are steps to identify the glass with poisonous liquid in it. 

1. Empty the glass 1 into another empty glass.

2. Take about 1/4th liquid from glass 2 and pour it into emptied glass 1.

3. Take 3/4th of liquid from glass 3 and pout it into glass 1.

Now, glass 1 has 1/4th of liquid from glass 2 and 3/4th from glass 3.

4. Now put glass 1 and glass 4 on the measuring scale.

    4.1 - If it weighs exactly 500 gm then it suggests that glass 1 had poison.
  
    4.2 - If it weighs between 500 - 505 grams (precisely 502.5 if exactly 1/4th of liquid was taken from glass 2 to glass 1) then obviously glass 2 is with poisonous liquid.

    4.3 - If it weighs between 505 - 510 grams (precisely 507.5 if exactly 3/4th of liquid was taken from glass 3 to glass 1) then obviously glass 3 is with poisonous liquid.

    4.4 - If it weighs exactly 510 gm then it suggests that glass 4 has poison.

 

Poisonous Drink

Marissa and Juliana went out for drinks together. They ordered the same drink. Juliana was really thirsty and finished five in the time it took Marissa to finish one. The drinks were poisoned, but only Marissa died. How?

TIP : Poison wasn't in Marrisa's glass neither added externally by any one.

This is how Juliana survived! 

Harmless Poisonous Drink

What was the incident?

That's because the poison was in the ice. Since Marissa took time to drink her first, the ice melted & poison got mixed up in the drink very well. Whereas, Juliana was thirsty & finished drinks in hurry; it didn't get enough time to melt the ice & hence poison didn't get mixed up with the drink. That's how Juliana survived!