Please help me Rachel is getting a sundae where the cost is proportional to the weight of the sundae she makes
Last time Rachel went she bought a 12-ounce sundae for $4.20. This time she buys a 17-ounce
sundae. Let c be the cost of the sundae. Set up a proportion to represent this situation.

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

How do you write something in scientific notation?

Combine like terms to make a simpler expression 3z+z