1. If the original unit price of a commodity is X, you can buy Y. According to the topic, you can get xy=0.8x(y+6)→0.2xy=4.8x→y=24.

That is, Xiaohua could have bought 24.

2. When the bottom area is 5x, 4x and y cm, the water depth is equal. Since the same amount of water is injected into the two containers, it can be obtained according to the topic.

5x(y- 10)=4x(y-6) gives y=26, y- 10= 16, that is, the water level of the large container will rise 16 cm.

3. Let ab be xkm apart. If A catches up with B in C, you will know that A is faster than B, and the total time from B to ab is 265,438+00 minutes. After 4 hours, 15 minutes =255 minutes,105: (255/210) = 7: 3, 4 hours, 65440 minutes.