Question

A first term of an AP is 5 last term is 45 and Sum is
400 find number of terms and
common difference Also find
S25-S20
​

Answer 1

Answer:

sum of n terms Sn -n2 (2a)+ (n-1)d

we know an =400 n=16 a=5

hence we got a common difference d=83 thus the number of term in AP= 16 and common difference d=83 this is your answer

Answer 2

Answer:

this is your answer

Step-by-step explanation:

thanks