lab

function solve(param){
   let grades = {};

   for(let el of param){
      let elements = el.split(' ');
      let name = elements.shift();
      let schoolGrades = elements.map(Number);

      if(!(grades.hasOwnProperty(name))){
          grades[name] = schoolGrades
      }else{
          schoolGrades.forEach(el =>{
            grades[name].push(el);
          })
      }
   }
   let output = Object.entries(grades).sort((a,b) =>{
      return avg(a[1]) - avg(b[1]);
   });

   for(let [key,value] of output){
      console.log(`${key}: ${value}`);
   }

   function avg(array){
      let sum = 0;
      for(let i = 0;i < array.length;i++){
         sum += array[i];
      }
      return sum / array.length;
   }
}
solve([ 'Lilly 4 6 6 5', 'Tim 5 6', 'Tammy 2 4 3', 'Tim 6 6' ]);