in a certain year the price of stock was 25% more than that of the stock B, While the price of stock C was 3/4th of stock A.

Question

Find the price of B

Answer 1

You haven't defined what

the price of stock was 25% more than that of the stock B

means. Which stock, A or C?

All we really know is that C = 3/4 A
So now supply the missing information, and you can answer the question.

Answer 2

assume
stock b = 1
stock a = 1+0.25
stock c =3/4 of 1.25 = 0.9375

Answer 3

Use the given sequance or general term to find the indicated Sum Sn S5