When 0≤x≤ 10, let the resolution function of y about x be y=kx+b,
Substituting points (0,-100) and (10,400) into the resolution function, we get:
{b=- 100 10k+b=400,
Solution: {k=50b=- 100,
So y=50x- 100(0≤x≤ 10),
∴s= 100x-(50x- 100)=50x+ 100(0≤x≤ 10);
(2) When 0≤x≤ 10, we know that 50x- 100=360.
So x=9.2, s = 50x+100 = 50x9.2+100 = 560,
When 10 < x ≤ 20, let y=mx+n,
Substitute the point (10,350) (20,850) into the resolution function,
Get { 10m+n=35020m+n=850,
Solution: {m=50n=- 150,
So y = 50x-150 (10 < x ≤ 20),
s = 100 x-(50x- 150)-50 = 50x+ 100( 10 < x≤20),
When y = 360,50x-150 = 360, the solution is x= 10.2.
So s = 50×10.2+100 = 610.
Answer: 920 tickets or 1020 tickets need to be sold, and the corresponding expenses are 56,000 yuan or 6 1000 yuan respectively.