Question

if 10 times the 10th term of an ap is equal to 15 times the 15 term show that 25 th fifth term of the ap is zero

Answer 1

Hey

Here is your answer,

according to question ,and

10x10th term =15x15th term

let a is the first term and d is the common difference .

10 (a+9d)=15 (a+14d)
5a+120d=0
a +24d=0

now ,
25th term =a+(25-1) d=a+24d=0
hence 25th term=0

Hence proved.

Hope it helps you!