Question

Onion is sold for 5 consecutive months at the rate of Rs 10, 20, 25, 25, and 50 per kg, respectively. A family spends a fixed amount of money on onion for each of the first three months, and then spends half that amount on onion for each of the next two months. The average expense for onion, in rupees per kg, for the family over these 5 months is closest to

• A. 18
• B. 26
• C. 16
• D. 20

Answer 1

The Correct Option is A

Suppose the family allocates Rs. 100 per month for the initial three months, followed by Rs. 50 per month for the subsequent two months. This results in them purchasing 10, 5, 4, 2, and 1 kilograms of onions during the first five months, respectively. In total, they acquire 22 kilograms of onions. Their total expenditure over these five months amounts to Rs. 400. To find the average cost per kilogram, we calculate:

\(Average \space Expense =\frac{ Total\space Expenditure }{Total \space Amount \space Bought }\)

= Rs.\(\frac{ 400 }{ 22}\) ≈ Rs. 18 per kilogram.

So the correct answer is option (A): 18.

Answer 2

Given that onions have been sold for Rs 10, 20, 25, 25, and 50 per kg over the past five months. 
Let's say that the total amount spent on onions over the course of these five months is 100, 100, 100, 50, 50. 
Therefore, the weight in kilograms for each of these five months should be 10, 5, 4, 2, 1, and so on. 
Over the course of these five months, the average cost per kilogram of onions was
\(=\frac{\text{total expense on onions in these five months}}{\text{total number of kgs of onions}}\)
\(=\frac{400}{22}=18.18\)