A shopkeeper buys a number of blue pens and red pens. He pack 3 blue pens and 2 red pens into a packets for sale. If he wants to obtain 160 packets of the pens he needs another 25 blue pens. What is the total number of the pens bought by him at first?
160*3 number he needs, he is short 25.
He bought 160*3-25.posted by bobpursley