diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..b14e30f
Binary files /dev/null and b/.DS_Store differ
diff --git a/lib/binary_to_decimal.rb b/lib/binary_to_decimal.rb
index 439e8c6..e3d7087 100644
--- a/lib/binary_to_decimal.rb
+++ b/lib/binary_to_decimal.rb
@@ -1,9 +1,10 @@
-# A method named `binary_to_decimal` that receives as input an array of size 8.
-# The array is randomly filled with 0’s and 1’s.
-# The most significant bit is at index 0.
-# The least significant bit is at index 7.
-# Calculate  and return the decimal value for this binary number using
-# the algorithm you devised in class.
+
 def binary_to_decimal(binary_array)
-  raise NotImplementedError
+  total = 0
+  exponent = binary_array.length - 1
+  binary_array.length.times do |index|
+    total += binary_array[index] * (2 ** exponent)
+    exponent -= 1
+  end
+  return total
 end