Number of books arranged in Class Two: 1 1.55×40=462 (Ben),

Class 3: 57015 = 38 (person)

Total number of three classes: 42+40+38= 120 (person),

The total number of books sorted by three categories: 588+462+570= 1620 (volume);

The average number of books arranged by each class in the three classes is1620 ÷120 =13.5 (Ben).

Fill in the form with data:

Statistics of sixth-grade students sorting books for the library

Articles? eye

Count? quantity

Ben. level

Number chart

The number of books per person is even.

The total number of books on science management is120162013.5. Class one 42 588 14 Class two 40 462? 1 1.55 three shifts 38 570? 15 As can be seen from the statistical chart, the average number of books arranged by each class in Class Two is lower than that of the whole grade.

So the answer is: two.