The price of 3 notebooks and 6 pen is Rs. 3000, With the same money one can buy a notebooks and 12 pen. Raju wants to buy 15 pen, how much will be have to pay?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. Rs. 3000.
Let's the price of a notebook = x
the price of a pen = y
The price of 3 notebooks and 6 pens is Rs. 3000:
⇒ 3x + 6y = 3000 (Equation 1)
With the same money, one can buy 1 notebook and 12 pens:
⇒ x + 12y = 3000 (Equation 2)
From Equation 2:
⇒ x + 12y = 3000
⇒ x = 3000 − 12y (Substitute this into Equation 1)
⇒ 3(3000 − 12y) + 6y = 3000
⇒ 9000 − 36y + 6y = 3000
⇒ 9000 − 30y = 3000
⇒ 6000 = 30y
⇒ y = 6000/30 = 200
the price of a notebook x = 3000 − 12 × 200 = 3000 − 2400 = 600
The price of one pen is Rs. 200. So,
Cost of 15 pens = 15 × 200 = 3000