Which two ratios are equivalent?

Question

(1)3/5 and 30/50
(2)5/8and 50/88
(3)6/11and66/110
(4)7/12and 49/80

Answer 1

3 / 5 = 3 / 5 ∙ 10 / 10 = 30 / 50 These two numbers are equal.

For the rest you use a calculator.

5 / 8 = 0.625 , 50 / 88 = 0.56818181 These two numbers are not equal.

6 / 11 = 0.545454545 , 66 / 110 = 0.6 These two numbers are not equal.

7 / 12 = 0.5833333 , 49 / 80 = 0.6125 These two numbers are not equal.