One day a store sold 20 sweatshirts. White ones cost $11.95 and yellow ones cost $12.50. In all, $247.25 worth of sweatshirts were sold. How many of each color were sold?

Let, white shirts = x

yellow shirts = y

x+y = 20, x=20-y

11.95x+12.50y=247.25

substitute value of x

11.95 (20-y) + 12.50y = 247.25

239-11.95y+12.50y = 247.25

0.55y = 8.25

y = 8.25/0.55 = 15

Now, substitute it 1st equation, x+15 = 20, x = 5

white sweatshirts = 5

yellow sweatshirts = 15