Question:
The 7th term of an arithmetic sequence is 0 and the 27th term is 60. What is the 17th term?
A0
B45
C30
D15
Answer:
C. 30
Explanation:
7th term= 0 a + 6d = 0 ......(1) 27th term= 60 a + 26d = 60 ......(2) (2) - (1) 20d = 60 d = 60/20 = 3 a + 6d = 0 a + 6 × 3 = 0 a = -18 17th term= a + 16d = -18 + 16 × 3 = -18 + 48 = 30