Glass of water

When 1/6 of the ice cube is above water then 5/6 is below it. The ratio of ice cube above water to below water is 1/5

When 1/7 of the ice cube is above water then 6/7 is below it. The ratio of ice cube above water to below water is 1/6

Hence option A

I think this one is A.

Let x be the fraction of the ice cube above the water. We are told that

1/7 < x < 1/6

Then for the lower bound of this range, the ratio of the mass above the water to the mass below is

(1/7)/(6/7) (1/7 above compared to 6/7 below)

=(1/7)*(7/6) = 1/6.

And, for the upper bound of the range, the ratio of the mass above the water to the mass below is

(1/6)/(5/6)

=(1/6)*(6/5) = 1/5.

So, we know the ratio of the mass above to the mass below will be between 1/6 and 1/5.