Question

question - If the ratio of the sum of the first n terms of two APs is ( 7n+1 ) : ( 4n+27 ) then find the ratio of their 9th terms..

PLEASE ANY ONE SOLVE THIS QUESTION WITH EXPLANATION...

DON'T GIVE ANY RUBBISH ANSWER....​

Answer 1

Answer:

64:63

Step-by-step explanation:

(7n+1):(4n+27)

n=9

7(9)+1 :4(9)+27

63+1 :36+27

64:63

Answer 2

Answer:

Given ratio of sum of n terms of two AP's = (7n+1):(4n+27) We can consider the 9th term as the m th

term.

Let's consider the ratio these two AP's m

th terms as am : a’m →(2)

Recall the nth term of AP formula, an = a +

(n-1)d

Hence equation (2) becomes,

am : a'm = a + (m − 1)d : a² + (m – 1)d' am : a'm = [2a + 2(m − 1)d] : [2a' + 2(m −

On multiplying by 2, we get

1)d']

= [2a + {(2m − 1) − 1}d] : [2a’ + {(2m – 1) – 1}

= =

d']

= S2m – 1: S'2m – 1 =

[7(2m − 1) + 1] : [4(2m − 1) +27] [from (1)] [14m – 7 +1] : [8m - 4 + 27]

= [14m – 6] : [8m + 23]

Thus the ratio of mth terms of two AP's is

[14m - 6] : [8m + 23].

now substitute the value of m as 9

so the answer becomes

120/95

I have given you right answer now