问题 解答题
(0.3+0.
3
)+(0.3×2+0.
3
×3)+
(0.3×3+0.
3
×5
)+…+(0.3×50+0.
3
×99
答案

根据题意可得:

(0.3+0.

3
)+(0.3×2+0.
3
×3)+(0.3×3+0.
3
×5
)+…+(0.3×50+0.
3
×99
),

=(0.3+0.3×2+0.3×3+…+0.3×50)+(0.

3
+0.
3
×3+0.
3
×5+…+0.
3
×99),

=0.3×(1+2+3+…+50)+

1
3
×(1+3+5+…+99),

=0.3×[(1+50)×50÷2]+

1
3
×[(1+99)×50÷2],

=0.3×1275+

1
3
×2500,

=382.5+833

1
3

=1215

5
6

单项选择题 A1型题
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