计算:(1+19/105)+(1+19/105×2)+(1+19/105×3)+…+(1+19/105×20)

问题描述:

计算:(1+

19
105
)+(1+
19
105
×2)+(1+
19
105
×3)+…+(1+
19
105
×20)

(1+

19
105
)+(1+
19
105
×2)+(1+
19
105
×3)+…+(1+
19
105
×20),
=(1+1+1+…+1)+(1+2+3+…+20)×
19
105

=20+(1+20)×20×
19
105

=20+21×20×
19
105

=20+76,
=96.