Answer:
3:1 or 30:10
Explanation:
You can simplify 15:5 further to 3:1
Or, you can increase it by however much you want, (think of a ratio as a fraction). Whatever you do to the numerator, you do to the denominator.
Example:
15:5 · (2/2)
= 30:10
Or, you can do:
15/5 · (3/3)
= 45:15
(You can multiply by 4, 5, 6, etc. just make sure to do it to both the numerator and denominator).
Whatever ratio you make equivalent to 15:5, ALWAYS has to equal three since when you simplify 15:5 further you get 3:1
If it makes it simpler for you, replace the colon marks with a dash to represent a fraction and then when you make an equivalent fraction just change the dash symbol back to the colon to represent a ratio.