Question

find the 20th term of ap whose 7th term is 24 less then the 11the term. find ​

Answer 1

Answer:

Let the first term, common difference and number of terms of an AP are a, d and n, respectively. Given that, first term (a)=12. Hence, the required 20th term of an AP is 126

Answer 2

Answer:

let first term =a =12and common difference =d in an AP

nth term =an =a+(n-1)d ---(1)

7th term =a7=a+6d-----(2)

a11=a+10d----(3)

given

a11-a7=24

a+10d-(a+6d)=24

a+10d-a-6d=24

4d=24

d=6--(4)

required term =a20

=a+19d

=12+19*6

=12+114

=126