Giza-IQ Test - Solution 17

Although the items appear to be binary numbers (i.e., numbers expressed in base 2), they are not.

1011, 1001, 1011, and 1010 are 31, 28, 31, and 30 expressed in base 3.  They are the number of days in January, February (not a leap-year), March, and April.

The four months that follow (May, June, July, and August) have 31, 30, 31, and 31 days.  Therefore, the correct answer is 1011, 1010, 1011, 1011.