diff --git a/lib/binary_to_decimal.rb b/lib/binary_to_decimal.rb
index 439e8c6..fcf93f0 100644
--- a/lib/binary_to_decimal.rb
+++ b/lib/binary_to_decimal.rb
@@ -5,5 +5,11 @@
 # 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
-end
+  total = 0
+  binary_array.each_with_index do |number, index|
+    exponent = 7 - index 
+    decimal = number * 2 ** exponent
+    total += decimal
+  end
+  return total
+end
\ No newline at end of file