Question 1077856
EQ1  X+Y=2500

EQ2  4X+4.5Y=10750

Rearrange EQ1 to solve for Y in terms of X    Y=2500-X

4X+4.5(2500-X) = 10750

4X -4.5X + 11250 = 10750

-.5X= -500

X= 1000

1000 units at $4 plus 1500 units at $4.5 add to exactly $10,750