3. A store sells three models of computers: $A$, $B$, and $C$. It is known that in July, the sales revenue of model $B$ accounts for $55\%$ of the total sales revenue of these three models. In August, the sales revenue of models $A$ and $C$ decreased by $12\%$ compared to July, but the store's total sales revenue increased by $10\%$ compared to July. Then, the sales revenue of model $B$ increased by ( ).
(A) $10\%$
(B) $16\%$
(C) $22\%$
(D) $28\%$
3. (D).

Let the sales revenue of model $B$ computers in July be $x$ yuan, and the sales revenue of models $A$ and $C$ computers be $y$ yuan. The sales revenue of model $B$ computers in August increased by $z \%$ compared to July. Then we have
$$
\left\{\begin{array}{l}
x=(x+y) 55 \%, \\
x(1+z \%) + y(1-12 \%) = (x+y)(1+10 \%) .
\end{array}\right.
$$

Solving this, we get $z \% = 28 \%$.