Lateral Thinking VIII and IX

[sstimson]

While that might work, is it a good way to get the bad coins mixed up with the good ones?

If you were doing this for real (  as in looking for lead slugs ) is it possible once you know that bad pile to take only the bad coins out with out mixing up them with the good ones?

Later

[S.H.]

Spoiler:

oh..sry..i assumed 1/100 gram for 1 coin (which is not faulty) and x is the mass for 1 faulty coin, was really sleepy last night so i didn't explain it clearly 

[bash7353]

Spoiler:

Assuming x is the weight of one not faulty coin, then the weight of a faulty coin is x+0.1g or x-0,1g. Now if we name the weight of the 55 measured coins y, then with this term you can determine which set is the faulty one:

(55x-y)/(0.1g)

Since the entity gramm is in x and also in y, it can be canceled so the result of this is without any entity.
The result might be negative, might be positive so you have to use the absolute value.

Edit: Spoiler-tags are now in the right position.

[Holmes]

Hey! If we continue this thread, it will become really popular! So, keep the problems on everyone.



*EDIT* Mathemathical problem

A clock is observed. The hour hand is exactly at the minute mark, and the minute hand is six minutes ahead of it. Later, the clock is observed again. This time, the hour hand is exactly on a different minute mark, and the minute hand is seven minutes ahead of it. How much time elapsed between the first and second observations?

[S.H.]

Spoiler:

2 + 12k hour and 12 minutes
where k is a non negative integer

[bash7353]

Question:

Spoiler:

Does it matter that there's only one possiblity for the first observation to be right, because if you put the hour hand onto a particluar minute mark the minute mark has to be on an specific spot, like if the hour hand point exacty onto the 5, then it is exacty 0500 hours, so the minute hand points onto the 12.
This all would be if the clock is very accurate, which most are not.

[Holmes]

Those are not solutions

There is a concrete time and answer.

[S.H.]

is my answer correct? 

[x64_02]

Spoiler:

1:12-3:24
two hours and 12 minutes

Which is basically what S.H. said.