Class A buys X bottles of water on the first day, and the water consumption on the second day is 70-X. If the water consumption on the second day is greater than that on the first day according to the known conditions, the water consumption on the second day is definitely greater than 30, but it is uncertain whether it is greater than 50. Now, we will discuss it in different situations:

The water purchase on the first day is in the range of 30-50, and the water purchase on the second day is also in the range of 30-50, so there are

3*0.8*70= 168, which obviously does not conform to 183 yuan. The water purchased on the first day should be less than 30, but this situation can be divided into two situations. The water purchased on the first day is less than 20, and the water purchased on the second day is more than 50, which is 3x+3 * 0.6 (70-x

The amount of water purchased on the first day is more than or equal to 20 and less than 30, and the amount purchased on the second day is 30-50, so it is 3X+3*0.8(70-X)= 183, and the solution X=25, which meets the requirements, so I bought 25 bottles on the first day and 70-25=45 bottles on the second day!

Hope to adopt!