diff --git a/examples/bal_problem.cc b/examples/bal_problem.cc
index c118f88..40d0fdf 100644
--- a/examples/bal_problem.cc
+++ b/examples/bal_problem.cc
@@ -37,6 +37,7 @@
 #include "Eigen/Core"
 #include "ceres/rotation.h"
 #include "glog/logging.h"
+#include "random.h"
 
 namespace ceres {
 namespace examples {
@@ -44,25 +45,6 @@
 typedef Eigen::Map<Eigen::VectorXd> VectorRef;
 typedef Eigen::Map<const Eigen::VectorXd> ConstVectorRef;
 
-inline double RandDouble() {
-  double r = static_cast<double>(rand());
-  return r / RAND_MAX;
-}
-
-// Box-Muller algorithm for normal random number generation.
-// http://en.wikipedia.org/wiki/Box-Muller_transform
-inline double RandNormal() {
-  double x1, x2, w;
-  do {
-    x1 = 2.0 * RandDouble() - 1.0;
-    x2 = 2.0 * RandDouble() - 1.0;
-    w = x1 * x1 + x2 * x2;
-  } while ( w >= 1.0 || w == 0.0 );
-
-  w = sqrt((-2.0 * log(w)) / w);
-  return x1 * w;
-}
-
 template<typename T>
 void FscanfOrDie(FILE* fptr, const char* format, T* value) {
   int num_scanned = fscanf(fptr, format, value);