diff --git a/bangdori/Maximum Average Subarray I.js b/bangdori/Maximum Average Subarray I.js
new file mode 100644
index 0000000..1be11e1
--- /dev/null
+++ b/bangdori/Maximum Average Subarray I.js	
@@ -0,0 +1,27 @@
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var findMaxAverage = function (nums, k) {
+  let maxSubSum = -Infinity;
+  let currSum = 0;
+  let lptr = 0,
+    rptr = 0;
+
+  for (let i = 0; i < nums.length; i += 1) {
+    rptr += 1;
+
+    if (rptr - lptr > k) {
+      currSum -= nums[lptr];
+      lptr += 1;
+    }
+
+    currSum += nums[i];
+    if (rptr - lptr === k) {
+      maxSubSum = Math.max(maxSubSum, currSum);
+    }
+  }
+
+  return maxSubSum / k;
+};