Answer:
A.) The sum of the product of the number of terms and the number of terms plus one.
Step-by-step explanation:
So, we have the sum of the first 22 positive even numbers:
S = 2 + 4+ 6 + ... + 44
We know the sum of such sequence is given by the (sum of the first number (2) and the last number (44)) multiplied by the number of terms (11).
S = (2 + 44) * 11 = 46 * 11 = 506
Answer A tells us it should be the sum of the number of terms (22) by the number of terms plus one (22 + 1 = 23).
S = 22 * 23 = 506
That's confirmed.
Answer B would give 22 * 21 = 462, so it's not right
Answer C would give 22 * 2 = 44, obviously not right
Answer D would give 22 * 22 = 484, close but not right.
