几道找规律的题 1,7,17,33,57,90,( ).A.123 B.133 C.142 D.1473,5,7,8,9,( ).A.10 B.11 C.12 D.131/4,1/3,1,5,( ).A.9 B.10 C.15 D.36

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几道找规律的题1,7,17,33,57,90,().A.123B.133C.142D.1473,5,7,8,9,().A.10B.11C.12D.131/4,1/3,1,5,().A.9B.10C.1

几道找规律的题 1,7,17,33,57,90,( ).A.123 B.133 C.142 D.1473,5,7,8,9,( ).A.10 B.11 C.12 D.131/4,1/3,1,5,( ).A.9 B.10 C.15 D.36
几道找规律的题
1,7,17,33,57,90,( ).
A.123 B.133 C.142 D.147
3,5,7,8,9,( ).
A.10 B.11 C.12 D.13
1/4,1/3,1,5,( ).
A.9 B.10 C.15 D.36

几道找规律的题 1,7,17,33,57,90,( ).A.123 B.133 C.142 D.1473,5,7,8,9,( ).A.10 B.11 C.12 D.131/4,1/3,1,5,( ).A.9 B.10 C.15 D.36
1.相邻项做差得6,10,16,24,33.此数列相邻项再做差得4,6,8,9.很遗憾是9不是10.这个数列是合数列,就是把质数都除去了的数列.所以下一项是10
从而6,10,16,24,33的下一项是43
所以选90+43=133
2.每一项加1得4,6,8,9,10这也是合数列.所以下一项是12
所以选12-1=11
3.这题我也拿不准.但是从倍数上来看分别是乘以了4/3,3,5.所以下一项应该至少是5*5=25.只有D满足要求
推测应该是这样解的:相邻项做商得4/3,3,5
这个数列再做差得5/3,2
把2写成8/4,则5/3,8/4的下一项应该是11/5(分子分母等差,恩,这个理由很牵强).所以4/3,3,5的下一项会是5+11/5=36/5
从而选5*36/5=36