Question

How many terms are there in Ap -1,-3,-5,...-151?

Answer 1

Hi !

The A.P is  -1,-3,-5,...-151

Here ,
first term = a = -1
common difference = d = -3 - (-1) = -2
last term = l = -151

To find :-
no: of terms = n  = ?

Let's use the formula :-

l = a + ( n - 1)d
-151 = -3 + ( n - 1) -2
-151 + 3 = (n - 1) -2
-148 = (n - 1) -2

n - 1 = -148/-2
n - 1 = 74
n = 74 +1
n = 75

Hence,
There are 75 terms in the A.P

Answer 2

there are 75
terms in Ap -1,-3,-5,...-151