An arithmetic sequence has a₇=80 and a₁₆=26. Find a₃₄.

01 / Standard#Your turn

Official paper · jm01-2023 · I.10 · PDF 3

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

There are nine common differences between the given terms.

Hint 2

Advance eighteen terms from a₁₆.

Worked solution

B: −82.

Checks and common pitfalls: Use index differences, not the indices themselves.

Reasoning checklist · self / teacher assessment

Teaching assessment checklist, independently authored. Use the original paper for official marks.
Find d.
$d=(26-80)/(16-7)=-6$
Evaluate the required term.
$a_{34}=26+18(-6)=-82$

Think first. Reveal a hint when the class is ready.

2023 JM01