Question

00 : 53

If p−1,p+3,3p−1p−1,p+3,3p−1 are in A.P. then ppis equal to:

Answer 1

Let suppose a, b, c are in Arithmetic Progression (AP) , then we know that,  

b-a = c-b

                                     

So here we can say that, 2b =  a+c --) 1

and now,  

1. a= p-1

2. b = p+ 3

3. c=3p-1

So that put b=3, and point 1 and 3 in equation 1 and we will get,  

-->  2*3 = p-1 + 3p-1

--> 6+2p = 4p - 2

8=2p

P=4

So that the value of P is 4