Rs 3500 is to be shared among three people so that the first person gets 50% of the second,

Let $x, y$ and $z$ be the amounts received by the first, second and the third person, respectively.

We have :

$x=50 \%$ of $y$

$=\frac{50}{100} y=\frac{1}{2} y$

$\therefore y=2 x$

Again, $y=50 \%$ of $z$

$=\frac{1}{2} z$

$\therefore z=2 y$

$=2(2 x)$

$=4 x$

Also, $x+y+z=3500$

Substituting the values of $z$ and $y$, we get:

$x+2 x+4 x=3500$

$\Rightarrow 7 x=3500$

$\Rightarrow x=500$

$\therefore y=2 x=2(500)$

$=1000$

$\therefore z=4 x=4(500)$

$=2000$

Thus, the amounts received by the first, second and the third person are Rs 500, Rs 1000 and Rs 2000 , respectively.