My approach:
We have total 8 cars, model A (blue, black, red, and green) & model B (blue, black, red, and green).
We can select cars in two ways:
1) 3 cars from model A (blue, black, red, and green) & 0 cars from model B (blue, black, red, and green) or 0 cars from model A (blue, black, red, and green) & 3 cars from model B (blue, black, red, and green).
2) 1 car from model A (blue, black, red, and green) & 2 cars from model B (blue, black, red, and green) or 2 car from model A (blue, black, red, and green) & 1 cars from model B (blue, black, red, and green)
Now selection
For 1) : 4C3*4C0 + 4C3*4C0 = 2* 4C3 = 8
For 2) : 4C1*3C2 + 4C1*3C2 = 2* 4C1*3C2 = 24 (3C2 coz we are only left with three options after choosing one car from other group)
Hence answer = 8+24 = 32