Question

  function A(a, b) {
     return a[b] * b;
   }
  function B(a) {

     var x = 0;
     for (var i=5; i>0; i--)
     x += A(a, i);

     return x;
  }
      var aValues = [3,5,9,8,7,1];
      var y = B(aValues);

Would the answer be:
B(1)
B(3)
B(5)
B(7)
B(8)
B(9)
?
Im lost be any push in the right direction would be appreciated.

Answer 1

After the execution y is 80.
The complete array is passed to B(). The loop in B() iterates over the last 5 elements of aValues. Arrays in Javascript start at index 0, so the loop i=5; i>0; i-- never touches the array element with index 0

Function a() then multiplies the current item with the current index and returns the result (which is added to x)

So for every loop index you get:

i=5 -> x += 1 * 5
i=4 -> x += 7 * 4
i=3 -> x += 8 * 3
i=2 -> x += 9 * 2
i=1 -> x += 5 * 1

So after the loop x contains the value 80 which is returned and assigned to y