let arr = [];
let newArr = [];
let k = 2;
while (true) {
arr.push(k);
k += 2;
if (arr.length === 30) {
break;
}
}
console.log(arr);
for (let i = 0; i < arr.length; i += 5) {
let str = 0;
for (let j = i; j < i + 5; j++) {
str += arr[j];
}
newArr.push(str / 5)
}
console.log(newArr);