Question

What is the number of terms in an AP given that its first and last term are 10 and -42 respectively and that its common differences is -4

Answer 1

Step-by-step explanation:

Let An= last term = -42

a= first term= 10

d= common difference= -4

n=?

An = a +(n-1)d

-42= 10+(n-1) -4

-42-10 = (n-1) -4

-52 =(n-1) -4

-52/-4= ( n-1)

13 = (n-1)

13+1 =n

Therefore, n = 14 i.e. number of terms = 14