Tom bought 34 pens and books altogether. Each pen costs $0.40 and each book costs $2.20. The difference between the cost of the pens and the cost of the books is $9.80. How many pens and how many books did Tom buy?
34 x 2.20 = $74.80 34 books
74.80 - 9.80 = $65 Difference too much, need to be reduced by this amount.
Note: Actually which item cost more was not given.
See alternative method below.
2.20 + 0.40 = $2.60 Exchanging 1 book for 1 pen, difference reduces by $2.60
65 / 2.60 = 25 pens Need to exchange 25 books for 25 pens
34 - 25 = 9 books
Tom bought 25 pens and 9 books.
Alternative method
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34 x 0.40 = $13.60
13.60 - 9.80 = $3.80 Assumption wrong!
2.20 + 0.40 = $2.60
3.80 / 2.60 = ?????????? Not a whole number.
13.60 + 9.80 = $23.40 Books should cost more than pens
2.20 + 0.40 = $2.60
23.40 / 2.60 = 9 books
34 - 9 = 25 pens
He bought 25 pens and 9 books.
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