Q6 of 105 Page 139

Check whether, -150 is a term of the AP: 11, 8, 5, 2 ….

Given first term (a) = 18

Common difference (d) = n₂-n₁ = 8 – 11 = -3

Let us consider -150 is a term in above series.

Then, a_n = -150

a_n = a + (n-1)d

-150 = 11 + (n-1)(-3)

-161 = (n-1)(-3)

n-1 =

n =

Since n is not an integer the given number is not in the series.

Find the number of terms in each of the following APs :

7, 13, 19, . . ., 205

Find the number of terms in each of the following APs :

18, 15, 13 …. , -47

Find the 31^st term of an AP whose 11^thterm is 38 and the 16^th term is 73

If the 3^rd and the 9^th terms of an AP are 4 and -8 respectively, which term of this AP is zero?

Questions · 105

6. Progressions

1 1 1 1 2 2 2 2 2 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 1 2 2 3 3 3 3 3 4 5 5 6 7 8 9 10 11 12 13 14 15 16 17 1 1 1 1 2 2 2 3 3 3 3 3 3 3 4 5 6 7 7 8 9 10 11 12 13 14 1 1 1 2 2 2 2 3 3 3 3 3 3 3 3 3 4 1 1 1 1 2 3 3 4 4 4 5 6 7