Marge purchased х
bicycle helmets and
y
tire pumps. Each helmet cost $15.00 and each pump cost $7.00. She purchased a total of
21 items and spent $219.00. How many helmets did Marge buy?

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label?