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What is the sum of the first 40 even positive integers?

Question

What is the sum of the first 40 even positive integers?

Options

A)
1,600
B)
1,560
C)
820
D)
1,640
E)
400

The correct answer is D.

Explanation:

The formula to be used is:
$$\text{N} + 1 \times \cfrac{\text{N}}{2} \times 2$$
$$\text{N} = 40$$
$$40 + 1 \times \cfrac{40}{2} \times 2$$

$$41 \times \cfrac{40}{2} \times 2$$
$$\cfrac{1640}{2} \times 2$$
$$820 \times 2$$
Therefore, the sum of the first 40 even positive integers $$= 1640$$

Dicussion (1)

• The formula to be used is:
$$\text{N} + 1 \times \cfrac{\text{N}}{2} \times 2$$
$$\text{N} = 40$$
$$40 + 1 \times \cfrac{40}{2} \times 2$$

$$41 \times \cfrac{40}{2} \times 2$$
$$\cfrac{1640}{2} \times 2$$
$$820 \times 2$$
Therefore, the sum of the first 40 even positive integers $$= 1640$$