Let the price of each garment be (10+x) yuan.

The profit of each garment is: 10+x-8=x+2.

It can sell 200-x/(0.5)× 10=200-20x every day.

According to the meaning of the question,

640=(x+2)(200-20x)

Solution, x=2 or 6

When x=2, the price of each garment is 12 yuan.

When x=6, the price of each garment is 16 yuan.