Question

Find the middle term of Ap: 6,13,20...216

Answer 1

$a = 6 \\ d = 7 \\ an = a + (n - 1)d \\ 216 = 6 +(n - 1)7\\ 210 = (n - 1)7 \\ n - 1 = 210 \div 7 \\ n = 30 + 1 = 31 \\ middle \: term = n + 1 \div 2 \\ 32 \div 2 = 16 \\ therefore \: 16th \: term \: of \: an \: ap \: is \: its \: middle \: term$

Answer 2

here is your required answer