Rita purchased 9 pens and 7 pencils for ₹66. Megha also bought 5 pens and 11 pencils of the same kind for ₹58. What is the cost of 3 pencils? |
₹9 ₹15 ₹6 ₹12 |
₹9 |
The correct answer is Option (1) → ₹9 Let the cost of a pen be $x$ and the cost of a pencil be $y$. According to the question: $9x + 7y = 66 \quad \text{(1)}$ $5x + 11y = 58 \quad \text{(2)}$ Multiply equation (1) by 5: $45x + 35y = 330 \quad \text{(3)}$ Multiply equation (2) by 9: $45x + 99y = 522 \quad \text{(4)}$ Subtract equation (3) from equation (4): $(45x + 99y) - (45x + 35y) = 522 - 330$ $64y = 192$ $y = \frac{192}{64} = 3$ Now substitute $y = 3$ in equation (1): $9x + 7(3) = 66$ $9x + 21 = 66$ $9x = 45$ $x = \frac{45}{9} = 5$ Therefore, cost of a pencil = $3$ Cost of 3 pencils = $3 \times 3 = 9$ |