BdMO Online Forum

Good Solution Hasib...and congratz for that one
Even some of the exam controllers got confused with this problem

Avik Roy wrote:Good Solution Hasib...and congratz for that one
Even some of the exam controllers got confused with this problem

yahooo! But, most importantly i found the solution while i was in bathroom i am feeling proud

now i can see that a genius is coming to the math era of Bangladesh from Khulna.

if the boy go, then also another boy will go; invesely if another boy go then the boy will go. Since u r my brain twin :loll:

whats the problem with my sollution bro...?:o

leonardo shawon wrote:whats the problem with my sollution bro...?:o

You wrote $P(A)=\{\Phi, emptyset\}$

Its wrong. Simply think, if $A=\{a\}$ what would be its power set? the $P(A)$ would be $\{\{a\},\Phi\}$ right?
Here $a$ is the only element of $A$. In our main problem $\Phi$ was also only element of $A$, so we should write

$P(A)=\{\{\Phi\}, \Phi\}$

btw, $\Phi$ and $emptyset$ means same thing. You need not to write both of them as element of a set.

thaaaaaaaankk yooouuu