Question 30
If the calculated answer is not an integer, give the nearest integer. If the calculated answer has more than five digits, give its last five digits.
The 6 by 6 grid below contains 1 to 36 in row order. A grid-aligned rectangle is good if the sum of its unit-cell numbers is divisible by 3. For example, the horizontal cells 1, 2 and the vertical cells 3, 9, 15 form good rectangles. How many good rectangles are there?
The 6 by 6 grid below contains 1 to 36 in row order. A grid-aligned rectangle is good if the sum of its unit-cell numbers is divisible by 3. For example, the horizontal cells 1, 2 and the vertical cells 3, 9, 15 form good rectangles. How many good rectangles are there?