Question : 30 pens and 75 pencils altogether were purchased for Rs. 510. If the average price of a pencil was Rs. 2, what was the average price of a pen?
Option 1: Rs. 9
Option 2: Rs. 10
Option 3: Rs. 11
Option 4: Rs. 12
Correct Answer: Rs. 12
Solution :
Total price = Price of 30 pens + Price of 75 pencils
⇒ 510 = Price of 30 pens + Price of 75 pencils ..........(1)
According to the question,
The average price of a pencil = Rs. 2
⇒ Total price of 75 pencils = 2 × 75 = Rs. 150
Putting in (1), we get,
⇒ 510 = Price of 30 pens + 150
⇒ Average price of a pen =
Hence, the correct answer is Rs. 12.