Question

if the sum of the n terms of an AP are in the ratio 7n+1:4n+27.find the ratio of 11th term​

Answer 1

1/2(2a+(n-1)d)/1/2(2A+(n-1)D)=7n+1/4n+27

2a+(n-1)d/2A+(n-1)D=7n+1/4n+27

Let n=21

2a+20d/2A+20D=7(21)+1/4(21)+27

2(a+10d)/2(A+10D)=148/111

a+10d/A+10D=148/111

a11/A11=148/111