Question 1: Let X be the number of stamps in 2 yuan and Y be the number of stamps in 0.8 yuan.

x+y=24

2x+0.8y=30

D: x=9，y= 15。

Question 2: There are X children and Y apples.

2x+ 13=y

3(x- 13)=y

De: x=52，y= 1 17。