CAT 1990 Question Paper Question 21

Question 21

Consider a function $$f(k)$$ defined for positive integers $$k = 1,2, ..$$ ; the function satisfies the condition $$f(1) + f(2) + .. = \frac{p}{p-1}$$. Where $$p$$ is fraction i.e. $$0 < p < 1$$. Then $$f(k)$$ is given by


$$\frac{-p}{1-p}$$ can be compared with sum of an infinite G.P. series i.e. $$\frac{a}{1-r}$$ (where a is first term and r is common ratio)
Hence here a=(-p)
and r = p
So kth term will be = $$(-p) (p)^{(k-1)}$$

Create a FREE account and get:

  • All Quant CAT Formulas and shortcuts PDF
  • 30+ CAT previous papers with solutions PDF
  • Top 500 CAT Solved Questions for Free


Boost your Prep!

Download App