diff --git a/src/binary-reversal/index.js b/src/binary-reversal/index.js
index 965bccf4..809f4e31 100644
--- a/src/binary-reversal/index.js
+++ b/src/binary-reversal/index.js
@@ -3,6 +3,18 @@
  *
  *  * @param {string} value
  */
-function binaryReversal(value) {}
-
-module.exports = binaryReversal;
+ function binaryReversal(value) {
+    // conversion of integar to binary
+        let toBinary = parseInt(value).toString(2);
+        // padding of the binary to 8 bits.
+        let padBinary = toBinary.padStart(8,0);
+        // split the padded binary,reverse and join.
+        let reversedBinary = padBinary.split('').reverse().join('')
+    // convert the reversed binary into digits and store in a variable finalNum
+     let finalNum = parseInt(reversedBinary, 2);
+    // return the final result
+     return `${finalNum}`
+     
+      }
+      module.exports = binaryReversal;
+    
\ No newline at end of file
diff --git a/src/list-sorting/index.js b/src/list-sorting/index.js
index 6636c20d..2b49ee07 100644
--- a/src/list-sorting/index.js
+++ b/src/list-sorting/index.js
@@ -1,3 +1,19 @@
-function listSorting(needle, haystack) {}
-
-module.exports = listSorting;
+function listSorting(needle, haystack) {
+    // if haystack is not a single array, return last index of haystack(needle).
+        if(!Array.isArray(haystack[0])){
+          return haystack.lastIndexOf(needle)
+      }
+      // loop through the haystack row using for loop in descending order
+      // loop through the haystack column to identify the last index(needle)
+      // if the last index of the colum exists, return row, column, else return -1.
+          for (let row = haystack.length-1; row >= 0; row--){
+              let col = haystack[row].lastIndexOf(needle)
+                  if (col !==-1){
+                      return [row, col]
+                  }
+          }
+          return -1
+      }
+      
+    module.exports = listSorting;
+