The ratio of the arithmetic mean of two numbers to one of the numbers is 5:9. What is the ratio of the smaller number to the larger number? Choose the correct choice from the following answers:
A) 1 : 5
B) 1 : 6
C) 1 : 7
D) 1 : 8
E) 1 : 9

Rationale: "for two numbers , the arithmetic mean is the middle of the two numbers . the ratio of the mean to the larger number is 5 : 9 , thus the smaller number must have a ratio of 1 . the ratio of the smaller number to the larger number is 1 : 9 . the answer is e ."
Answer: E