text: function solve(arr){
      let result = '';
      for(let i = 0; i < arr.length; i++){
          if(i % 2 === 0){
              result += arr[i] + " ";
          }
      }
      console.log(result.join(' '));
  }
  
  function solve2(arr){
      return arr.filter((_, i) => i % 2 === 0).join(' ');
  }
  console.log(solve2(['20', '30', '40']));