(a) To simplify the ratio 25:75, we can divide both numbers by their greatest common divisor. The greatest common divisor of 25 and 75 is 25. Dividing both numbers by 25, we get 1:3. Therefore, the simplified ratio is 1:3.
(b) To simplify the ratio 7:14:35, we can divide all three numbers by their greatest common divisor. The greatest common divisor of 7, 14, and 35 is 7. Dividing all three numbers by 7, we get 1:2:5. Therefore, the simplified ratio is 1:2:5.