Help me in solving PPSCPP142 problem

help
,
1

My issue

i can understand the problem .Can you explain the logic of this code.
cout << ceil(a / 5.0) - ceil(b / 5.0) << “\n”;

My code

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int t, a, b;
    cin >> t;
    for (int i = 1; i <= t; i++) {
        cin >> a >> b;
        cout << ceil(a / 5.0) - ceil(b / 5.0) << "\n";
    }
    return 0;
}

Learning course: Complete C++ course
Problem Link: CodeChef: Practical coding for everyone

2

@rr2731
we are subtracting the unchanged persons from the total persons , its simple maths .