diff --git a/lab3_task1_funcation_block_arg/main.rb b/lab3_task1_funcation_block_arg/main.rb
new file mode 100644
index 0000000..fac45b4
--- /dev/null
+++ b/lab3_task1_funcation_block_arg/main.rb
@@ -0,0 +1,11 @@
+def task1(array)
+    indices = array.each_with_index.to_a
+    sorted_indices = indices.sort_by { |(element, index)| -element }
+    result = sorted_indices.map { |(element, index)| index }
+    result
+end
+  
+# Ex
+array = [5, 3, 8, 1, 7]
+puts "Indices in order of decreasing elements:"
+puts task1(array).join(", ")