He can have 6 pages with 6 cards each 12 pages with 3 cards each 3 pages with 6 cards each and 6 with 3 cards each so 6 6 page 5 6 page 2 3 pages 4 6 page 4 3 pages so 7 ways
The ratio of areas is the square of the ratio of perimeters (or any linear measure). Then the ratio of perimeters is the square root of the ratio of areas: .. √(16/49) = 4/7