Answer:
11. 40/100 = 4/10
12. 2/5 = 4/10
13. 4/10 = 8/20
Step-by-step explanation:
A fraction can be written as a/b where b is the total number of divisions and a is the number of parts that you take.
So, for 11, the fraction is:

Because there are 100 parts and 40 of them are colored.
So, to find another equivalent fraction we can divide every number by 10 as:

In the same way, for 12, we get:

For 13, we get:
