A factory plans to recruit a and b workers 180, and the monthly salary is shown in the table. If the number of workers recruited in A is X, two workers are paid.

(1) if the number of class a workers is x, the number of class b workers is (180-x).

So the total salary y =1500x+2000 (180-x) =-500x+360000,

So the functional relationship between y and x is: y =-500 x+360000;

(2) The number of jobs in ∫ B is not less than 2 times that in A,

∴ 180-x≥2x，

∴x≤60，

∵-500