Question

5 times the 5 th term of an A.P. is equal to 12 times the 12 th term. Find the 17 th term .

Answer 1

let in AP ,first term =a and common difference =d
5th term= a+4d
12th term =a+11d
5 times of 5th term = 12 times of 12th term

5(a+4d) =12(a+11d)
5a+20d= 12a+132d
0= 12a+132d-5a-20d
0=7a+112d
divide each term with 7
0= a+16d
a+16d =0
17th term =0 since 17th term of AP is a+16d