The total cost of 12 pens and 5 pencils is equal to Rs.111. Also, the cost of 1 pencil is Rs.5 less than the cost of 1 pen. What will be the cost of 8 pens and 9 pencils?
Correct Answer: Description for Correct answer:
Let the cost of 1 pencil = x
Cost of 1 pen = (x + 5)
According to the question,
\( \Large 12 \left(x+5\right) + 5x = 111 \)
=> \( \Large 12x + 60 + 5x = 111 \)
=> \( \Large 17x = 111 - 60 = 51 \)
=> \( \Large x = \frac{51}{17} = 3 \)
CP of 1 pencil = Rs.3
CP of 1 pen = Rs.8
Total CP of 8 pens and 9 pencils
\( \Large \left(8 \times 8\right) + \left(9 \times 3\right) \)
\( \Large Rs. \left(64 + 27\right) = Rs.91 \)
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