JS Daily #7 - Block Scoped Let

What is the output of following code?

var a = 10;
  let a = 20;

Output is 10.

First a variable a is declared in global scope using var and initialized with value 10. Then, a new block scoped variable a is declared using let and assigned with value 20. The block scoped variable works only within the block(ie inside the curly brackets{}). So, again outside the block, the printed a is the global a with value 10.