How to find the dual of a system if there is multiplication of 2 variables?

Question

I am trying to find the dual of the following system.

$Min$ $\sum_{i=0}^k x_i$

$s.t.$

$\sum_{i\in K}^ka^k_{i}x_i>=b_{i}$

$x_i>=0$

$a^k_{i}=1/0$

I could not be sure because instead of A matrix, we have a binary variable($a_i$).