Suppose you buy several pens at a discount store. all the pens are the same price, and you buy as many pens as the cost (in cents) of each pen. the pens cost a total of $1.44. how many pens did you buy?

Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?

Daniel bought a computer game for $25 and later sold it to thomas for a 40% profit. how much did daniel sell the computer game for?

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?