If $a:b = 1:3$ and $b$ is a positive, one-digit integer, what is the greatest possible value of $a$?

=========================================

Work Shown:

a:b = 1:3

a/b = 1/3

a*3 = b*1 ... cross multiply

3a = b

b = 3a

Since b is a one digit number, this means that the largest it can get is 9

The largest possible value of 'a' is 3

1. d.90

2. e. none of these (80)

3. a. 0

4. b. 6

5. e. none of these (10)

6. a. 5