430+3* 100X=3730

300X=3300

X= 1 1

(2) Method1; 3 *100 *15+430 = 4930 (yuan)

Method 2; 3730* 1=3730 (yuan)

2。 Y=(2.3-2)X+(4500-X)*(3.5-3)

Y=2250-0.2X

2250-0.2 *10000 =1150 (yuan)

3。 There are x people in a triple room and (50-X) people in a double room.

X/3=50-X/2

X=30

30/3= 10 (person) (50-30)/2= 10 (room)

300*8- 13*400*0.4=3040 (yuan)

3040-1510 =1530 (yuan)