Step-by-step explanation:
25:15 is equivalent to 5:3 because 25 is 5 times 5, and 15 is 5 times 3.
10:1 is not equivalent to 5:3 because the sides cannot be multiplied to get 10:1.
3:9 is not equivalent to 5:3 because 5:3 has a bigger numerator and a smaller denominator, while 3:9 has it swapped.
