Question

for an AP first term is -7 and last term is 53 . if the sum of all terms is 483 , then find the number of terms and the common difference
Arethematic Progression
plz step by step ​

Answer 1

Answer:

a=-7

l=53

Sn = 483

Sn =n/2(a+l)=n/2(-7+53)= n/2×46=23n

So, 23n=483

n=21

So, an =53

a+(n-1)d = 53

-7+(21-1)d =53

20d = 60

d=3

Number of terms is 21 and common difference is 3