Tea Money
Written on 10:35 pm by Vja Students
A drinks machine offers three selections - Tea, Coffee or Random (Either tea or Coffee) but the machine has been wired up wrongly so that each button does not give what it claims.
If each drink costs 50p, how much minimum money do you have to put into the machine to work out which button gives which selection?
Answer::
You have to put just 50p.
Put 50p and push the button for Random. There are only 2 possibilities. It will give either Tea or Coffee.
· If it gives Tea, then the button named Random is for Tea. The button named Coffee is for Random selection. And the button named Tea is for Coffee.
· If it gives Coffee, then the button named Random is for Coffee. The button named Tea is for Random selection. And the button named Coffee is for Tea.
Thus, you can make out which button is for what by putting just 50p and pressing Random selection first.
50 ps
only one drink can tell you the correct which-is-which.
first take a drink from selection labelled random..it cannot be the selection which really ives the random drink...if it gives coffee it is tea and vice-versa.
hence one is fixed.lets say that tea is fixed. now the selection which is named coffee can be tea or random, but since tea is fixed it has to be random and hence selection named tea is coffee