The first terms of the arithmetic progression are added. What is the sum?

Answer and explanation

Correct answer: A.

  1. Step 1: The tenth term is . Step 2. . Answer: 100. Why not the others: uses a wrong last term, forgets the division by , and is a sum for a different progression.

Practise more Mathematics A: Functions, Calculus, Complex Numbers and Probability.

Free questions with an explanation for every one, and full timed Exames Nacionais Secundário (Portugal) mock tests.