Question

Find the average of 1³ + 2³ + 3³ + 4³ .....+ 20³.
1. 2202
2. 2200
3. 2205
4. 2204

Answer 1

Correct Answer - Option 3 : 2205

Given:

Number of terms = 20 

Formula used:

Average = [n(n + 1)/2]² × (1/no. of terms)

Where n is number of term.

Calculation:

Average = [(20 × 21)/2]² × 1/20

⇒ Average = (10 × 10 × 21 × 21)/20 = 2205

∴ The answer will be 2205.