Question

A.

8 + 12 + 16 + 20; 56

c.

8 + 12 + 16 + 20; 120

b.

8 + 16 + 32 + 64; 56

d.

8 + 16 + 32 + 64; 120


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Answer 1

a. 8 + 12 + 16 + 20; 56

Explanation:

`\sum\limits_(k=2)^54k\\\\\text{Make a sum with components equal to 4k,}\\\text{ where k = 2, k = 3, k = 4 and k = 5}:\\\\4(2)=8\\4(3)=12\\4(4)=16\\4(5)=20\\\\8+12+16+20=56`