The price of a notebook has risen to $3.90 today. yesterday's price was $3.40 . find the percentage increase. round your answer to the nearest tenth of a percent.

Agreeting card company can produce a box of cards for $7.50. if the initial investment by the company was $50,000, how many boxes of cards must be produced before the average cost per box falls to $10.50?

Explain how you can use the associative property to evaluate (7x50)x4.

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?