The sum of the fourth and twelfth term of an arithmetic progression is 20. What is the sum of the first 16 terms of the arithmetic progression?  Choose the correct option
A) 300 B) 120 C) 150 D) 160 E) 270
n th term of A.P. is given by a+(n-1)d   4 th term = a+3d   12 th term = a+11d   Given a+3d+a+11d=20 --&gt; 2a+14d=20 --&gt; a+7d = 10   Sum of n term of A.P = n/2[2a+(n-1)d]   subsitiuing n = 16 ...we get 15/2[ 2a + 14d] = 16 [a+7d] = 16*10 = 160...   Answer is 160...
<result>D</result>
The sum of the fourth and twelfth term of an arithmetic progression is 20. What is the sum of the first 16 terms of the arithmetic progression?