If the 7th term of an arithmetic progression is 18 and the 14th term is 45, what is the sum of the first 20 terms of the progression?
A. 630
B. 650
C. 670
D. 690
Answer:C
If the 7th term of an arithmetic progression is 18 and the 14th term is 45, what is the sum of the first 20 terms of the progression?
A. 630 B. 650 C. 670 D. 690