The answer is 24/45
Let's check out all choices:
a) 6:10 = 3:5
6 * 5 = 10 * 3
30 = 30
Therefore, equivalent!
b) 6:10 = 9:15
6 * 15 = 10 * 9
90 = 90
Therefore, equivalent!
c) 6:10 = 48:80
6 * 80 = 10 * 48
480 = 480
Therefore, equivalent!
d) 6:10 = 24:45
6 * 45 = 10 * 24
270 ≠ 240
Therefore, inequivalent!