1 statue mile in the UK = 1760 yards, = 1760 * 3 feet.
So 9 UK status miles = 47520 feet. Divide that by 3,000 gives an L
ration of just under 16 which I gather is well within the bounds for a modern commercial plane such as the A320.
However the arrival height is zero (not good unless there is a runway right ahead) and assumes no significant headwind or sink.
A nautical mile is pretty much 6,000'. If that is what was meant then the L
goes up to 18 which is (I suspect) a pretty significant increase.