Answer:
y = 17.5
It says y is proportional to x, and y = 35 when x = 140, but we don't know what y is when x = 70. So since y is proportional to x and x = 140 we have to find out how 140 gets to 70, and that is dividing by 2 because 70 is half of 140. So then you would just divide the previous y value, 35, by 2, and you would get 17.5. And there you go, you've got you're answer.