Question

for every 5 coins Carmen gets, she gives 2 to her brother Frankie. If Carmen has 9 coins, how many does Frankie have?

Answer 1

Lets write this as a ratio 1st.

When Working with ratios we have to be VERY careful because you HAVE to put the numbers for the ratio in the way it says. If you change the order than your changing the answer. Ratio's can be written in 3 different ways.
 
Like this:-  

a to b
a:b
$\frac{a}{b}$

For every 5 coins Carmen gives Frankie 2

5:2

9:?

5 - 2 = 3

So 3:2

9 ÷ 3 = 3

3 × 2 = 6

So, Caamen has 9 coins and Frankie has 6 coins.

Hope I helped ya!!! xD 

Answer 2

We set up a proportion: 2/?= 5/9

Cross multiply:
5*?= 2*9
⇒ ?= 2*9/5= 3 3/5 

Frankie would have 3 3/5 coins if Carmen had 9 coins~