There is a rectangle in Uncle Zhou's yard.

Solution: 1 Chinese cabbage planted by Zhou Bobo accounts for 5/ 12 of this land.

Chinese cabbage and lettuce planted by Zhou Bobo account for 5/24 of this land respectively.

2. 12* 12*(2/3)=96(m？ )

3. The vegetable area planted by Grandpa Zhou: 96*(5/8)=60(m? )

The area of Chinese cabbage planted by Zhou Bobo is 96*(5/ 12)=40(m? )

Zhou Bobo's lettuce planting area: 96*(5/24)=20(m? )