2. If the books assigned to the fifth grade are regarded as 1, then the books assigned to the fourth grade are 0.8, the books assigned to the sixth grade are 1.2, and the sum of the three grades is * * =1+0.8+1.2 = 3, that is to say/kloc. So level 4 =400*0.8=320 (Ben); Level 5 =400* 1=400 (Ben); Grade 6 =400* 1.2=480 (Ben).
3. The number of the last three piles is the same. At this time, the number of each pile =36 divided by 3 =12;
A gave one-fifth of himself to B, and the rest was four-fifths, which is 12, so the original quantity of A = 12 divided by (four-fifths) =15; And you can know that a gave B 3；;
B gave C a quarter, and the rest were three quarters, which is 12, so the number of pieces in B's hand before giving C was = 12 divided by three quarters = 16, and of this 16, three were given by A, so B originally had/kloc.
Original quantity C =36- 15- 13=8.
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