using find
let numbers = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
function multipleOf13(element, index, array) {
return (element % 13 == 0) ? true : false;
}
console.log(numbers.find(multipleOf13));
console.log(numbers.findIndex(multipleOf13));