**Solution**:

Let the ages of Sachin and Amit be $7 x$ and $4 x$.

From the question,

$$

\begin{aligned}

& 7 x+4 x=33 \\

\Rightarrow & 11 x=33 \\

\therefore \quad & x=\frac{33}{11}=3 \text { years }

\end{aligned}

$$

Now, the Age of Sachin $=7 x$

$$

\begin{aligned}

&=7 \times 3 \\

&=21 \text { years } \\

\& \text { the age of Amit } &=4 \times \\

&=4 \times 3 \\

&=12 \text { years }

\end{aligned}

$$

$$

\text { Befor } 6 \text { years their ages will be }

$$

$21-6=15$ years $\& 12-6=6$ years

$\therefore \quad$ Ratio $=\frac{15}{6}=\frac{5}{2}=5: 2 ;$ Ans.

$\therefore \quad$ Correct option is $(\mathrm{d})$

Trick :

Sachin : Amit

$$

\begin{array}{l}

\quad 7 \quad: 4 \\

\Rightarrow \quad: 7+4=33 \\

\Rightarrow \quad 1=3 \\

\Rightarrow \quad: 2=6 \\

\therefore \quad \text { After } 6 \text { years the required } \\

\text { Patio }=(7-2):(4-2)=5: 2 ; \text { Ans. }

\end{array}

$$