The first equation would be
3000 C + 5000 T = 137,000,000 (total sales)
The second equation would be
3000*.20*C + 5000*.30*T = 27,000,000 (profit)
This can be rewritten
600 C + 1500 T = 27,000,000
Now solve those two equations for C and T, the number of cars and trucks sold, using either method.