Akshat added Birthday-paradox-problem in Basic Maths

Basic Math/Birthday-paradox-problem/Birthday-paradox-solution.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+using namespace std;
+// C++ program to approximate number of people in Birthday Paradox
+// problem
+// Returns approximate number of people for a given probability
+int find(double p)
+{
+    if (p != 1)
+        return ceil(sqrt(2 * 365 * log(1 / (1 - p))));
+    else return 366;
+}
+int main()
+{
+
+/*#ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+#endif*/
+    cout << find(0.50);
+}
+

Basic Math/Birthday-paradox-problem/Problem-statement.txt

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+How many people must be there in a room to make the probability 100% that at-least two people in the room have same birthday?
+
+Answer: 367 (since there are 366 possible birthdays, including February 29).
+
+How many people must be there in a room to make the probability 50% that at-least two people in the room have same birthday?
+Answer: 23
+The number is surprisingly very low. In fact, we need only 70 people to make the probability 99.9 %.