$arr1: Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 )
sumArray($arr1): 10
$arr2: Array ( [0] => 18.64 [1] => 26.78 [2] => 13.3 [3] => 4 )
sumArray($arr2): 62.72
$arr3: Array ( [0] => 56 [1] => 8 [2] => 91 )
sumArray($arr3): 155