diff --git a/src/NuGetUtility/Wrapper/HttpClientWrapper/FileDownloader.cs b/src/NuGetUtility/Wrapper/HttpClientWrapper/FileDownloader.cs
index e8d1fd7..6a038e7 100644
--- a/src/NuGetUtility/Wrapper/HttpClientWrapper/FileDownloader.cs
+++ b/src/NuGetUtility/Wrapper/HttpClientWrapper/FileDownloader.cs
@@ -31,7 +31,7 @@ public async Task DownloadFile(Uri url, string fileNameStem, CancellationToken t
                     {
                         return;
                     }
-                    await Task.Delay((int)Math.Pow(EXPONENTIAL_BACKOFF_WAIT_TIME_MILLISECONDS, i + 1), token);
+                    await Task.Delay(EXPONENTIAL_BACKOFF_WAIT_TIME_MILLISECONDS * ((int)Math.Pow(2, i)), token);
                 }
             }
             finally
@@ -71,7 +71,7 @@ private async Task<bool> TryDownload(string fileNameStem, Uri url, CancellationT
             {
                 extension = "txt";
             }
-            string fileName = fileNameStem + "." + extension;
+            string fileName = $"{fileNameStem}.{extension}";
 #if NETFRAMEWORK
             using FileStream file = File.OpenWrite(Path.Combine(_downloadDirectory, fileName));
 #else