Question
Risa and Yen have some pens. If Risa gives 15 pens to Yen, Yen will have 4 times the number of pens as Risa. If Yen gives 17 pens to Risa, Risa will have 12 as many pens as Yen. How many pens does Risa have at first?
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Risa and Yen have some pens. If Risa gives 15 pens to Yen, Yen will have 4 times the number of pens as Risa. If Yen gives 17 pens to Risa, Risa will have 12 as many pens as Yen. How many pens does Risa have at first?