Evaluate the sum. $$\sum _ { k = 1 } ^ { 400 } 7$$
A)4
B)400
C)2,805
D)2,800
E)7

Name: Evaluate the sum. \[\sum _ { k = 1 } ^ { 400 } 7\] A)4 B)400 C)2,805 D)2,800 E)7
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Question

Evaluate the sum.​ $$\sum _ { k = 1 } ^ { 400 } 7$$ ​
A)4
B)400
C)2,805
D)2,800
E)7

Quizplus · Accepted Answer

The sum can be evaluated by adding the digits of each number and then adding those sums together. Doing this, we get: 
1 + 1 + 9 + 9 + 13 + 11 + 11 + 2 + 9 + 4 + 1 + 2 + 9 + 4 + 0 + 9 + 3 + 4 + 1 + 2 + 6 + 8 + 9 + 5 + 0 + 10 + 11 + 0 + 0 
= 100 
Therefore, the answer is 2,800 (since 100 multiplied by 28 equals 2,800).

Evaluate the Sum ∑k=14007\sum _ { k = 1 } ^ { 400 } 7k=1∑400​7

Evaluate the Sum $\sum _ { k = 1 } ^ { 400 } 7$