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Mathematics
Mathematics
Problem
Calculate the value of
∑
k
=
1
20
(
3
+
4
(
k
−
1
)
)
\displaystyle \sum_{k=1}^{20} \bigl(3 + 4(k-1)\bigr)
k
=
1
∑
20
(
3
+
4
(
k
−
1
)
)
. a)
860
860
860
b)
820
820
820
c)
1640
1640
1640
d)
800
800
800
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