## Dhaka Higher Secondary 2011/4

Problem for Higher Secondary Group from Divisional Mathematical Olympiad will be solved here.
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Please don't post problems (by starting a topic) in the "Higher Secondary: Solved" forum. This forum is only for showcasing the problems for the convenience of the users. You can post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.
BdMO
Posts: 134
Joined: Tue Jan 18, 2011 1:31 pm

### Dhaka Higher Secondary 2011/4

\begin{align*} a + b + c + d + e =& 1\\ a - b + c + d + e =& 2 \\ a + b - c + d + e =& 3\\ a + b + c - d + e =& 4\\ a + b + c + d - e =& 5\end{align*}
Find $a$ from the above set of equations.

leonardo shawon
Posts: 169
Joined: Sat Jan 01, 2011 4:59 pm
Location: Dhaka

### Re: Dhaka Higher Secondary 2011/4

what does form mean... Anyone please explain...
Ibtehaz Shawon
BRAC University.

long way to go .....

HandaramTheGreat
Posts: 135
Joined: Thu Dec 09, 2010 12:10 pm

### Re: Dhaka Higher Secondary 2011/4

leonardo shawon
Posts: 169
Joined: Sat Jan 01, 2011 4:59 pm
Location: Dhaka

### Re: Dhaka Higher Secondary 2011/4

$a+b+c+d+e=1$ its equation 1.

$a-b+c+d+e=2$ from equation 1 $a+c+d+e=1-b$ so $b=-1/2$
by doing same in each equation, i have got $a=6$ b=-0.5 c=-1 d=-1.5 and e=-2

if im wrong, please give the correct sollution and whats the meaning question. Somebody please make it clear to me. ! ! !
Ibtehaz Shawon
BRAC University.

long way to go .....

Tahmid Hasan
Posts: 665
Joined: Thu Dec 09, 2010 5:34 pm

### Re: Dhaka Higher Secondary 2011/4

i also came up with 11
Last edited by Tahmid Hasan on Sun Jan 30, 2011 10:30 pm, edited 1 time in total.
বড় ভালবাসি তোমায়,মা

leonardo shawon
Posts: 169
Joined: Sat Jan 01, 2011 4:59 pm
Location: Dhaka

### Re: Dhaka Higher Secondary 2011/4

HandaramTheGreat wrote:$a+b+c+d+e=1$ $b+c+d+e=1-a$

if we add all the 5 equations, we'll get
$5a+4(b+c+d+e)=15$ $5a+4(1-a)=15$ $\therefore a=11$

If we add 5 equations, we get
$5a+3(b+c+d+e)=15$
$5a-3a=15-3$
$a=6$
Ibtehaz Shawon
BRAC University.

long way to go .....

HandaramTheGreat
Posts: 135
Joined: Thu Dec 09, 2010 12:10 pm

### Re: Dhaka Higher Secondary 2011/4

sorry...

leonardo shawon
Posts: 169
Joined: Sat Jan 01, 2011 4:59 pm
Location: Dhaka

### Re: Dhaka Higher Secondary 2011/4

its okay Bro... dont worry.
Ibtehaz Shawon
BRAC University.

long way to go .....

farhan
Posts: 4
Joined: Thu Apr 05, 2012 12:06 pm

### Re: Dhaka Higher Secondary 2011/4

it was a very easy one....hohoho...bt many got perplexed..