Since the great circle of 1/3 is a black part, it can be known that the area of the great circle is unit 6 and the area of the white part is unit 4;

Since 2/5 of the small circle is black, we can know that the area of the small circle is unit 5; The area of the white part is unit 3;

The area of the white part of two circles is unit 7. Namely: 4+3=7.

The ratio of the area of the black part to the area of the white part in the two circles is 2: 7.