At the local aquarium there are 10 dolphins 8 penguins and 4 whales what is the ratio of penguins to whales

A ratio compares two quantities.

penguins = 8
whales = 4

8:4 , now simplify

8/4 = 2
4/4 = 1

2:1 is the ratio.

Final 2:1

A ratio compares 2 or more quantities. But when working with ratios you have to be VERY careful. What ever says to come in the ratio 1st it HAS to come first, cause if you change the order it will mess the ratio up. A ratio can be written in 3 ways:- 

a to b
a:b


Now lets look at the information we have:-

10 - dolphins
8 - penguins
4 - whales  

Now we need to find the ratio of penguins to whales. So it would look like this:-

penguins: whales
penguins to whales

 
Penguins:- 8
Whales:- 4 

So, the ratio of penguins to whales would look like:- 

8 to 4
8:4


Now we will simply 

8 ÷ 4 = 2
4 ÷ 4 = 1 

So, our new simplified ratio would be:-  2 to 1. 2:1. .

Hope I helped ya!!