One math problem every day in grade three.

(1) according to the meaning of the question, you can get the profit of each commodity and the total sales volume of the commodity, and you can get the functional relationship between y and X.

(2) According to the meaning of the question, the vertex form of the quadratic function is obtained by using the matching method, and then the maximum value of y when x=5 is obtained.

Solution: Solution: (1) Suppose the price of each commodity rises by X yuan (X is a positive integer).

Then the profit of each commodity is: (60-50+x) yuan,

Total sales: (200- 10x) pieces,

Commodity profit is:

y=(60-50+x)(200- 10x)，

=( 10+x)(200- 10x)，

=- 10x2+ 100x+2000。

∵ The original price of each piece in 60 yuan cannot be higher than that in 72 yuan.

∴ 0 < x ≤ 12 and x is a positive integer;

(2)y =- 10 x2+ 100 x+2000

=- 10(x2- 10x)+2000，

=- 10(x-5)2+2250。