Average Problem 3

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Kathy bought seven pens. Out of this, four pens were priced one dollar each. The cost of the rest three pens are 30 cents each. Find the average cost of each pen?

Solution: Total cost of the pens = 4 x 100 cents+ 3 x 30 cents
=400 cents + 90 cents
= 490 cents.
Hence, average cost of each pen = 490/7 cents = 70 cents