a town had 2120 acres of pine trees a few years ago. only 15% of the acres of trees are left. how many acres of pine trees remain?

What is the size of the matrix resulting from

Abike shop sells you a bicycle for $63 and a helmet for $21. the total cost is 150% of what the shop spent originally. how much did the shop spend originally? how much profit did the bike shop earn by selling the bicycle and helmet to you ?

Which term best describes the association between variables a and b