Could you please post the rest of the question? Its kinda difficult to explain something when we dont even know what's being asked.

linfongyu probably meant this:

If three things are in a ratio of 5:9:11, what does the total number of things have to be a multiple of?

25 (the sum of the numbers)

If the number of things represented by the 5 doubles, can you represent the new ratio as 10:9:11?

Yes, multiplication and division are okay

If you add 6 things to the the number of things represented by the 9, can you represent the new ratio as 5:15:11?

No, not unless you know the absolute number

If the number of things represented by the 9 is reduced by one-third, can you represent the new ratio as 5:7:11?

No, but you could represent it by 5:6:11

linfongyu wrote:i don't even understand the question. please help! from a "refresher" question!

If you add 6 things to the the number of things represented by the 9, can you represent the new ratio as 5:15:11?

If the number of things represented by the 9 is reduced by one-third, can you represent the new ratio as 5:7:11?

Hi,

Always remember one thing..
when there is a ratio given, lets say 2:3 for mangoes & apples, what actually given is 2X:3X, where X is the number you need to multiply with 2 to get to the nbr of Mangoes &
need to multiply with 3 to get to the nbr of Apples.

Because we always deal in ratios directly, we forget to consider this simple thing & make many mistakes/
so if Mango/Apple = 2:3, do you know how many mangoes or apples do you have. NO
but if you know that X = 10, then you know that you have 20 mangoes & 30 apples.
Now if you add 6 mangoes, what happens..
tha ratio become 20+6/30. is it equal to (2+6)/3.
it is not, right? it is 26/30 = 13/15

so while dealing with ratios, addition or substraction from denominator or Numerator changes the ratio, a lillte differently than a multiplication or division will change.

if it is not clear, let me know.

regards
ritz