The housekeeping department of Red Sun Hotel has triple rooms, double rooms and single rooms. The charging data are shown in the following table (for example, 50 yuan per person per day for a triple r

The housekeeping department of Red Sun Hotel has triple rooms, double rooms and single rooms. The charging data are shown in the following table (for example, 50 yuan per person per day for a triple room. Answer: Answer: ① We rent a triple room X and a double room Y.

3x+2y = 503×50x+2×70y = 15 10÷50%，

X = 8y = 13，

∴ 8 triple rooms and 13 double rooms;

② There are (50-x) people living in the double room.

According to the meaning of the question, y=[50x+70(50-x)]×50%.

That is, y =-10x+1750 (0 ≤ x < 50, x is an integer);

(3) Because the two rooms are just full, the value of x is a multiple of 3, and (50-x) is still a multiple of 2.

So some points on the image are: (0, 1750) (6, 1690) (12, 1630) (18,1570) (.

④ It is not the minimum cost, because y decreases with the increase of x, so the minimum cost is 1270 yuan when x=48.