10x+4y+(9-x-y)*3=52

Pack up, take it

7x+y=25

The integer solution of (x, y) is: (1, 18), (2, 1 1), (3,4).

Because x+y

2. There are X bikes and 36-x tricycles.

2x+3*(36-x)=89

Solution, x= 19

So there are 19 bicycles and 36- 19 tricycles = 17.

3. do right for x and wrong for y.

3x-2y=50

3x=50+2y

x= 16+2/3*( 1+y)

Since both x and y are integers, y+ 1 must be a multiple of 3.

The integer solutions of (x, y) are: (18,2), (20,5), (22,8), ...

Because x+y≤20, the solution of this problem is:18,2.

4. Set Hag X and Nezha y.

X+3y=36 gives x=6.

8x+6y= 108 y= 10

So, Hag 6, Nezha 10.

5, don't understand the equation:

Analysis: Add 1Kg to pour out half of the original, which is equivalent to only 1/2, and then pour in 1Kg, which is equivalent to 3/5 of the original. This extra part (3/5- 1/2) is the ratio of 1Kg.

The original weight of wine is:1/(3/5-1/2) =10 kg.

6、

Mango seen by the prince: 3/( 1- 1/2)=6.

2 Mango seen by the prince: 6/( 1- 1/3)=9.

Mango seen by the big prince: 9/(1-1/4) =12.

Mango seen by the Queen:12/(1-kloc-0//5) =15.

Mango seen by the king:15/(1-kloc-0//6) =18.

So the total number of mangoes is 18.

7、

144 * 29/ 143 = ( 143+ 1) * 29/ 143 = 143 * 29/ 143+29/65438.

18/(2/9+ 1/6)= 18/(7/ 18)=324/7