Arithmetic Reasoning - Expert Level Question 36 – answer, explanation & discussion

We know that in A.P series

18th term = a + 17d

29th term = a + 28d

But given

a + 17d = 29..........(i)

a + 28d = 18......... (ii)

Solving equation (i) and (ii), we get

d = -1

put d = -1 in any of the above equations and we get,

a = 46

Now, we know 49th term can be written as, a + 48d

putting the value of a and d in the above equation,

a + 48d = 46 + 48(-1)

= 46 - 48

= -2

Hence, the 49th term is -2.