What is the average of the cubes of the first 5 natural numbers?

We need to find the average of the cubes of the first 5 natural numbers:

1³= 1

2³= 8

3³= 27

4³= 64

5³= 125

Sum of these cubes

= 1 + 8 + 27 + 64 + 125 

= 225

Average of 225:

= $$\frac {225}{5}$$

= 45

Thus, correct option is (a).