Question

Find the number of terms in the following AP, 18,151

2

,13,……….., - 47.​

Answer 1

Answer:

n = 27

Step-by-step explanation:

Given;

18,151/2,13, ...., -47

a (or) t1 = 18

d=t2-t1

= 15(1/2)-18

= 2(1/2)  

= -5/2  

Let number of terms = n

tn = -47  

→ a+(n-1)d = -47

→ 18+ (n-1) (-5/2) = -47

→ (n-1) (-5/2) = -47 - 18

→ (n-1) (-5/2) = -65

→ n-1 = (-65)×(-2/5)

→ n-1 = 130/5

→n - 1 = 26

→ n = 26 +1

→ n = 27

Therefore,

Number of terms = 27