clc 
// Given that
n = 3 // no. of half lives
// Sample Problem 11 on page no. 12.35
printf("\n # PROBLEM 11 # \n")
printf("Standard formula used \n")
printf(" N = 2^(-n) ...... fraction after n half lives.\n")
f = (1 / 2)^n
printf("\n Fraction of sample left after %d half lives is %f . ",n,f)