Solution: If the chicken has X heads, the rabbit has 6-X heads.
2X
+
4(6-X)= 1
20
The solution is X=2.
Then there are 2 chickens, 6-2=4 rabbits.
2. Analysis: The same reason
Solution: If the chicken has X heads, the rabbit has 1 1-X heads.
2X
+
4( 1 1-X)= 1
36
The solution is X=4.
Then there are 4 chickens, 1 1-4=7 rabbits.
3. solution: if the number of chickens is x, the number of rabbits is 5-X.
2X
+
4(5-X)= 14
The solution is X=3.
Then there are 3 chickens and 5-3 rabbits = 2.
4. Analysis: Same as above
Red+green = 14kg,
Red 1 kg 120 yuan, how much red is (120* red) yuan and green is (160* green) yuan.
Solution: let black tea be x kg and green tea be 14-X kg.
120X
+
160( 14-X)= 1
2080
The solution is X=4.
Then black tea is 4 kg, and green tea is 14-4= 10 (kg).