Question

find the number of terms in each of the following APs: (1) 7,13,19,........,205 (2) 18,31/2,13,......-47

Answer 1

In (1) l=a+(n-1)d
205=7+(n-1)6
205-7=(n-1)6
198/6=n-1
33+1=n
N=34

in (2) l=a+(n-1)d
-47=18+(n-1)-5/2
-47-18=(n-1)-5/2
-65*(-2/5)=n-1
26+1=n
N=27

hope this will help u

Answer 2

Heya Friend ✋✋✋

(1) 7 , 13 , 19 ......., 205

a = 7

d = 6

an = 205

an = a + ( n - 1 ) d

205 = 7 + ( n - 1 ) 6

198 = ( n - 1 ) 6

n - 1 = 33

n = 34


(2). 18 , 31 / 2 , 13 ..... - 47

a = 18

d = - 2.5

an = - 47

an = a + ( n - 1 ) d

-47 = 18 + ( n - 1 ) (-2.5)

-65 = ( n -1 ) (-2.5)

n - 1 = 26

n = 27

Hope it helps