Easy Trick

Lets say the mass of the brick is x.

$x = 1 kg + 0.5x$

$0.5x = 1 kg$

$x = 2 kg$

Thus the mass of the brick is 2 kg.

$Let\quad the\quad mass\quad of\quad the\quad brick\quad be\quad x\quad kg\\ Given:\\ 1kg\quad plus\quad half\quad of\quad the\quad weight\quad of\quad the\\ brick\quad equals\quad the\quad weight\quad of\quad the\quad brick.\\ i.e.\\ \quad \quad \quad \quad \quad 1\quad +\quad \frac { x }{ 2 } \quad =\quad x\\ \Longrightarrow \quad x\quad -\quad \frac { x }{ 2 } \quad =\quad 1\\ \Longrightarrow \frac { x }{ 2 } \quad =\quad 1\\ \Longrightarrow \boxed { x\quad =\quad 2\quad kg }$

Let $M$ be the mass of the weird brick. Then

$M=1+\dfrac{1}{2}M$ $\implies$ $M-\dfrac{1}{2}M=1$ $\implies$ $\dfrac{1}{2}M=1$ $\implies$ $\boxed{M=2~kg}$

You can solve it arithmetically, or just logically:

if the bricks mass == 1 + $\frac{1}{2}$ the bricks mass, it means that 1 has to be the other half of the bricks mass, otherwise this equation could be never correct.

Let the weight of the brick be x. Now,question says that the weight of the brick is 1+half the weight of brick. So the equation is 1+x/2=x.

1=x-x/2.

1=x/2

2=x

Just check the multiple choice answers. "2kg" is the only one which works! Or look at a clever solution.

let total mass be T then (T/2)+1=T, (T+2)/2=T, T+2=2T, 2kg=T