Question

find the number of term in the list of A.P 6,11,16,21 ...whose sum is 969​

Answer 1

Answer:

The given A.P is :-6,11,16,21..

First term- 6

Common difference- 21 - 16 = 16-11= 11-6= 5

Step-by-step explanation:

n/2[2a+(n-1)d] = 969

n/2[2× 6 + (n-1) 5]= 969

n/2[ 12+5n-5]=969

n[12+ 5n - 5]= 969× 2

12n + 5n^ - 5n= 1938

5n^+7n= 1938