The first term of an arithmetic sequence is -2 and the common difference is -3. What is the 10th term?
Answer and explanation
Correct answer: D. -29
- Step 1: a_n = a_1 + (n - 1)d.
- Step 2: a_10 = -2 + 9 x -3 = -29.
Answer
-29.
Why not the others: -32 uses n instead of n - 1; -26 uses n - 2; the second value treats the sequence as geometric.
Practise more Probability, counting and sequences.
Free questions with an explanation for every one, and full timed Psychometric Entrance Test (PET Israel) mock tests.
More Probability, counting and sequences questions
- A bag has 4 red and 5 blue marbles. Two marbles are drawn one after the other without replacement. What is the probability that both are red…
- A club has 8 members. In how many ways can a committee of 2 be chosen?
- A geometric sequence has first term 5 and common ratio 3. What is the 4th term?
- What is the median of the data set 15, 9, 15, 10, 3, 13, 12?
- A bag has 3 red and 4 blue marbles. Two marbles are drawn one after the other without replacement. What is the probability that both are red…
- A club has 10 members. In how many ways can a committee of 2 be chosen?