The second analytical formula is Y2 = 25× 0.9×10+4.5x (x ≥10).
Solve equation 200+5x=225+4.5x,
D: x=50,
∴ When x < 50, y 1 < y2, adopt the first scheme;
When x=50, y 1=y2 can be used in two schemes;
When x > 50, Y 1 > Y 2 adopts the second scheme.