## Search found 172 matches

- Mon Jan 31, 2011 9:48 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/3
- Replies:
**16** - Views:
**6720**

### Re: Dhaka Higher Secondary 2011/3

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...

- Sun Jan 30, 2011 11:30 am
- Forum: Secondary Level
- Topic: Largest value of (x+y)
- Replies:
**4** - Views:
**2031**

### Re: Largest value of (x+y)

$x,y \in \mathbb N$

- Sun Jan 30, 2011 7:31 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/3
- Replies:
**16** - Views:
**6720**

### Re: Dhaka Higher Secondary 2011/3

Hey . $\Phi $ is a

**set**. $A=\{\Phi\}$ is not an empty set. It has an element which is $\Phi$. If they said $A=\Phi$ then we could say $A$ is an empty set.- Sun Jan 30, 2011 7:28 am
- Forum: Secondary: Solved
- Topic: Dhaka Secondary 2011/1 (Higher Secondary 2011/1)
- Replies:
**9** - Views:
**8042**

### Re: Dhaka Secondary 2011/1 (Higher Secondary 2011/1)

The answer isn't the one Tahmid posted,it is as follows- The answer is 76. Here we must know that in the silver ring set,there are 12 kinds,and in the gold ring set,there are 10 kinds.So at least 2 kinds of silver ring is different from the gold kinds.Now if we pick up 75 rings , all of them can be...

- Sat Jan 29, 2011 9:33 pm
- Forum: Secondary Level
- Topic: Largest value of (x+y)
- Replies:
**4** - Views:
**2031**

### Largest value of (x+y)

$x,y \in \mathbb N$. Find the largest value of $(x+y)$ such that \[20x+11y=2011\]

- Sat Jan 29, 2011 2:28 pm
- Forum: Secondary: Solved
- Topic: Dhaka Secondary (Higher Secondary) 2011/5
- Replies:
**9** - Views:
**4375**

### Re: Dhaka Secondary (Higher Secondary) 2011/5

Please write full solution so that someone can tell whether you are right or wrong or where is your fault...

*to hide something write : [ h i d e ] text [ / h i d e ] (without spaces)

*to hide something write : [ h i d e ] text [ / h i d e ] (without spaces)

- Sat Jan 29, 2011 11:44 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/9
- Replies:
**11** - Views:
**10068**

### Re: Dhaka Higher Secondary 2011/9

Solution: Base $2$ representation of $1952$ is $11110100000$ So, $1952=2^{10}+2^9+2^8+2^7+2^5$ $\Rightarrow f(1952)=f(2^{10}+2^9+2^8+2^7+2^5)$ $=f(2^{10})+f(2^9)+f(2^8)+f(2^7)+f(2^5)$ As, $f(2^n)=f(2^{n+2})$, $f(2^{10})=f(2^8)=f(2^6)=f(2^4)=f(2^2)=f(2^0)$ Similarly $f(2^9)=f(2^7)=f(2^5)=...=f(2^1)$ ...

- Sat Jan 29, 2011 9:46 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/9
- Replies:
**11** - Views:
**10068**

### Re: Dhaka Higher Secondary 2011/9

Is the first relation valid for $n =0$ and the second relation valid for all $X \subset \mathbb N\cup \{0\}$ ?

*edited

*edited

- Sat Jan 29, 2011 9:44 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/3
- Replies:
**16** - Views:
**6720**

### Re: Dhaka Higher Secondary 2011/3

Ah.. guys are getting closer. One said $B=\Phi$, another said $B=\{\Phi\}$. What's next?

You should explain your answers ...

You should explain your answers ...

- Sat Jan 29, 2011 7:51 am
- Forum: H. Secondary: Solved
- Topic: Dhaka Higher Secondary 2011/3
- Replies:
**16** - Views:
**6720**