solving algebraic equation
posted by tanya .
For college orientation week,Mike sold 200 shirts.sweat shirts were priced at $50.00 each ant tshirts at $20.00 each Mike receive a total of $6250.00 for the shirts. How many type of shirt dud Mike sell for college orientation week ?please help and show a equation to solve

Mike sold
X sweat shirts.
Y TShirts.
Eq1: X + Y = 200 Shirts.
Eq2: 50x + 20y = $6250.
Multiply Eq1 by 20 and add the 2 Eqs:
20x  20y = 4000
+50x + 20y = 6250
Sum: 30x = 2250
X = 75 Sweat shirts.
In Eq1, substitute 75 for X:
75 + Y = 200,
Y = 125 Tshirts.