Question

in a certain Ap,the 32nd term is twice the 12th term.Prove that 70th term is twice the 31st term.

Answer 1

32nd term = 2 ( 12th term)
a + 31 d = 2(a + 11 d)
a+ 31d = 2a + 22 d
a = 9d
Now,
70th term = 2 (31st term)
a + 69d = 2 (a + 30d)
a + 69d = 2a + 60d
9d + 69d = 18d + 60d
78 d = 78 d

Hope this will help u

Answer 2

same as above answer