7kg of tea costing Rs. 280 per kg is mixed with 9kg of tea costing Rs. 240 per kg. The average price per kg of the mixed tea is

Correct option is A

Given: 7kg of tea costing Rs. 280 per kg is mixed with 9kg of tea costing Rs. 240 per kg. 

Formula used:

$$\text{Average Price} = \frac{(w_1 \times p_1) + (w_2 \times p_2)}{w_1 + w_2}$$

​Where:
 w₁ and w₂ are the weights (amounts of tea),
p₁ and p₂ are the prices per kg of the two types of tea.

Solution:

$$\text{Average Price} = \frac{(w_1 \times p_1) + (w_2 \times p_2)}{w_1 + w_2}$$

​​$$\text{Average Price} = \frac{(7 \times 280) + (9 \times 240)}{7 + 9}$$​
​$$= \frac{(1960) + (2160)}{16}$$​
​$$= \frac{4120}{16}$$​​​
= 257.50
The average price per kg of the mixed tea is Rs. 257.50.

Thus, the correct answer is (a).