Correct Answer - Option 3 : Rs. 7.66

**Given****∶**

Raman buys potatoes at Rs. 6, Rs. 8 and Rs. 10 per kg for three successive years.

Money spend on potatoes each year = Rs. 1500

**Formula Used****∶**

Average = Sum of observations / Number of observations

**Calculation****∶**

Total quantity of potatoes consumed in 3 successive years = Rs. [(1500 / 6) + (1500 / 8) + (1500 / 10)] = Rs. [1500 × {1 / 6 + 1 / 8 + 1 / 10}] = 1500 × (47 / 120) = Rs. (70500 / 120)

Total amount spent = Rs. (1500 × 3) = Rs. 4500

Average cost = (4500) / (70500 / 120) = Rs. 7.66

**∴ the average cost is Rs. 7.66 per kg of potatoes.**