Question
The average cost price of 12 pens (having equal cost
price) decreased by Rs.2, when one of the pen is replaced by a new pen having cost price of Rs.80. Find the cost price of the pen that was replaced.Solution
Let the cost price of each pen be Rs.x So, cost price of 12 pens = Rs.12x According to the question, => (12x – x + 80)/12 = x – 2 => 11x + 80 = 12x – 24 => x = 104 Therefore, the cost price of the pen that was replaced is = Rs.104
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