One day a store sold 28 sweatshirts. White ones cost $9.95 and yellow ones cost $13.50. In all, $321.20 worth of sweatshirts were sold. How many of each color were sold?
The store sold 16 white and 12 yellow sweatshirts.
Let's call the number of white sweatshirts sold
We also know and can write:
From the first equation we can substitute
We can now substitute