An arithmetic progression has first term and common difference . Find the sum of the first 25 terms.
Answer and explanation
Correct answer: A. 1550
- Step 1: . Step 2. . Answer: 1550. Why not the others: 3050: That multiplies the last term by instead of using the average of the first and last. 122: That is only the 25th term. 1555: That is off by one common difference.
Practise more Sequences, series and expansions.
Free questions with an explanation for every one, and full timed Singapore GCE A-Level mock tests.
More Sequences, series and expansions questions
- An arithmetic progression has first term and common difference . Find the sum of the first 20 terms.
- An arithmetic progression has first term and common difference . Find the sum of the first 15 terms.
- An arithmetic progression has first term and common difference . Find the sum of the first 12 terms.
- An arithmetic progression has first term and common difference . Find the sum of the first 18 terms.
- An arithmetic progression has first term and common difference . Find the sum of the first 30 terms.
- A geometric progression has first term and common ratio . Find the sum to infinity.