Question

Which term of A.P. 3,10,17........... will be 84 more than its 13 th term

Answer 1

Step-by-step explanation:

a = 3

d = 10 - 3 = 7

13th term= a + 12 d

= 3 + 12 × 7

= 3 + 84 = 87

Now adding 84 to it

= 87 + 84

= 171

añ = 171

a + (n - 1)d = 171

3 + (n-1)7 = 171

(n - 1)7 = 171 - 3

(n - 1) × 7 = 168

n - 1 = 168/7

n - 1 = 24

n = 24 + 1

n = 25

so 25th term will be 84 more than 13th term

Answer 2

GIVEN :

AP = 3, 10, 17......

First term of AP = a = 3

Common Difference = a2 - a1 = 10 - 3 = 7

Thirteenth term = a + 12d

= (3) + 12(7)

= 3 + 84

= 87

Add 84 to the thirteenth term.

= 87 + 84

= 171

In an AP nth term = a + (n - 1)d

an = a + (n - 1)d

171 = 3 + (n - 1)7

171 = 3 + 7n - 7

171 = 7n - 4

7n = 171 + 4

7n = 175

n = 175/7

n = 25

Therefore, 25th term will be 84 more than its 13th term.