Hi, hope this helps :)
Feel free to ask me if you do not understand. I used the elimination method.
Well there both even numbers so the gcf factor would have to be even also
60 = 1,2,3,4,5,6,10,12,15,20,30,60
72 = 1,2,3,4,6,8,9,12,18,24,36,72
The Gcf would be 12
There are 12 months in a yr so 12/3=4 then 1/3x4=4/3 so 1ft and 1/3 erode each yr. C is the correct answer<span />
2 = 2????
Thats what Im getting it from.
Since x is 2 then it would still be 2=2 in simple term.