If you have a line that measures 25 cm. and you scale the line by 5,what would the length of the new line be?

At a sale this week, a desk is being sold for $213. this is a 29% discount from the original price. what is the original price?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

Can someone answer this question for me