diff --git a/README.md b/README.md
index dc8f5ce..bfcf8ca 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,8 @@ Solutions in various programming languages are provided. Enjoy it.
 17. [Robot Bounded In Circle](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/17-Robot-Bounded-In-Circle)
 18. [Best Time to Buy and Sell Stock](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/18-Best-Time-to-Buy-and-Sell-Stock)
 19. [Sequential Digits](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/19-Sequential-Digits)
+23. [Gas Station](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/23-Gas-Station)
+28. [Subarray Product Less Than K](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/28-Subarray-Product-Less-Than-K)
 
 ## August LeetCoding Challenge
 Click [here](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/) for problem descriptions.
diff --git a/September-LeetCoding-Challenge/28-Subarray-Product-Less-Than-K/Subarray-Product-Less-Than-K.cs b/September-LeetCoding-Challenge/28-Subarray-Product-Less-Than-K/Subarray-Product-Less-Than-K.cs
new file mode 100644
index 0000000..abf7444
--- /dev/null
+++ b/September-LeetCoding-Challenge/28-Subarray-Product-Less-Than-K/Subarray-Product-Less-Than-K.cs
@@ -0,0 +1,17 @@
+public class Solution {
+    public int NumSubarrayProductLessThanK(int[] nums, int k) {
+        int len = nums.Length;
+        int p = 1;
+        int i=0, j=0, total=0;
+        while(j < len){
+            p *= nums[j];
+            while(i<=j && p>=k){
+                p /= nums[i];
+                i++;
+            }
+            total += (j-i+1);
+            j++;
+        }
+        return total;
+    }
+}