问题 解答题
(1+
19
92
)+(1+
19
92
×2)+(1+
19
92
×3)+…+(1+
19
92
×15)
答案

(1+

19
92
)+(1+
19
92
×2)+(1+
19
92
×3)+…+(1+
19
92
×15),

=15+

19
92
×(1+2+3+…+15),

=15+

19
92
×120,

=39

18
23

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