Question

The average price of gold during last year was Rs. 1,120 per gram. The average in the first five months was Rs. 1,105. In the next three months, the average was Rs. 1,125. What was the average price in the remaining months?
1. Rs. 1,135
2. Rs. 1,140
3. Rs. 1,137.50
4. Rs. 1,130

Answer 1

Correct Answer - Option 1 : Rs. 1,135

Given: 

The average price of gold during last year was Rs. 1,120 per gram. In the first five months average was Rs. 1,105 and in the next three months, the average was Rs. 1,125

Concept: 

Average = (Sum of all observations/number of observations)

Calculation:

Let the average price of gold for the remaining four months is 'Y' rupees

According to the question

The average price of gold during last year is 

⇒ [(5 × 1105) + (3 × 1125) + (Y × 4)]/12 = 1120

⇒ (5525 + 3375 + 4Y) = 1120 × 12

⇒ 8900 + 4Y = 13440

⇒ 4Y = 13440 - 8900

⇒ Y = 4540/4

⇒ 1135 rupees

∴ The average price of gold in the remaining month of the year is 1135 rupees.