How Many Decades Are in a Century?

Answer: There are ten decades in a century.

Explanation: 

We know that in a decade, there are 10 years. 

We also know that in a century there are 100 years. 

Hence, if we try to find the decades in a century (100 years), we get: 

1 decade = 10 years 

? decades = 100 years

Thus, simplifying it further, we get:

10 decades = 100 years = 1 century. 

Thus, There are ten decades in a century.