Habiba, this is the solution:
a. We have 15 odd and 15 even tiles, therefore the ratio is:
15 : 15, written in its simplest form: 1:1
For every odd tile, there is an even.
b. We have the following perfect squares:
1, 4, 9, 16, and 25. Therefore, we have:
5 perfect squares and 25 non-perfect squares.
Therefore, the ratio is 5:25,
written in its simplest form: 1:5
For every perfect square, there are five non-perfect squares.
c. We have the following composite numbers:
4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30. Nineteen in total. Let's recall that a composite number can be defined as the whole numbers that have more than two factors.
And we have the following prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29. Ten numbers in total. Let's recall that a prime number has no positive integer divisors other than 1 and itself.
In consequence the ratio in its simplest form is: 10:19, but if we consider 1 as a prime number, the ratio would be: 11:19.