Red apples cost $\$1.20$ per pound and green apples cost $\$1.50$ per pound.  

1. Write an expression to represent the total cost of $x$ pounds of red apples and $y$ pounds of green apples.

   Answer (a):

   $1.20x+1.50y$

2. What is the total cost if you buy $3$ pounds of red apples and $2$ pounds of green apples?

   Hint (b):

   Substitute $3$ for $x$ and $2$ for $y$.

   More Help (b):

   $1.20(3)+1.50(2)=\\ 3.60+3.00=\\ $6.60$