Algoritms tasks

Jamie loves sleeping. One day, he decides that he needs to wake up at exactly hh: mm. However, he hates waking up, so he wants to make waking up less painful by setting the alarm at a lucky time. He will then press the snooze button every x minutes until hh: mm is reached, and only then he will wake up. He wants to know what is the smallest number of times he needs to press the snooze button. A time is considered lucky if it contains a digit '7'. For example, 13: 07 and 17: 27 are lucky, while 00: 48 and 21: 34 are not lucky. Note that it is not necessary that the time set for the alarm and the wake-up time are on the same day. It is guaranteed that there is a lucky time Jamie can set so that he can wake at hh: mm. Formally, find the smallest possible non-negative integer y such that the time representation of the time x·y minutes before hh: mm contains the digit '7'. Jamie uses 24-hours clock, so after 23: 59 comes 00: 00.

          window.onload = function() {
            var hours,
                minutes, 
                outputAnswer = document.querySelector('.answer span'),
                snoozeInterval, 
                inputSnoozeInterval = document.querySelector('input[data-function="snooze"]'),
                inputTime = document.querySelector('input[data-function="time"]'),
                time,
                result = 0,
                luckyNumber = 7;
                
            inputTime.onchange = function() {
                readData();
                findLuckyHours(snoozeInterval, hours, minutes);
            };
        
            inputSnoozeInterval.onchange = function() {
                readData();
                findLuckyHours(snoozeInterval, hours, minutes);
            };
            
            function readData() {
                snoozeInterval = +document.querySelector('input[data-function="snooze"]').value;
                time = document.querySelector('input[data-function="time"]').value.split(' ');
                hours = +time[0];
                minutes = +time[1];
            }
        
            function  findLuckyHours(snoozeInterval, hours, minutes) {        
        
                if (checkConditions(hours, minutes, snoozeInterval)) {
                    outputAnswer.innerHTML = result;
                    return;
                }        
        
                result = 0;
        
                while (!(hours % 10 == luckyNumber || (hours / 10) % 10 == luckyNumber || minutes % 10 == luckyNumber || (minutes / 10) % 10 == luckyNumber)) {
                    if (minutes < snoozeInterval) {
                        hours--;
                        minutes += 60;
                    }
                    
                    if (hours < 0) hours = 23;
                    
                    minutes -= snoozeInterval;
                    result++;
                }
                
                outputAnswer.innerHTML = result;
            }
        
            function checkConditions(hours, minutes, snoozeInterval) {
                if (hours > 23 || hours < 0 || !hours) {
                    result = 'Incorrect hours. Please change it.';
                    return true;
                }
        
                if (minutes > 59 || minutes < 0 || !minutes) {
                    result = 'Incorrect minutes. Please change it.';
                    return true;
                }
        
                if (snoozeInterval < 0 || !snoozeInterval) {
                    result = 'Incorrect snooze interval. Please change it.';
                    return true;
                }
        
                return false;
            }
        };

Task 1