import java.util.*;

public class Main {
 	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
	    int n = sc.nextInt();
	    StringBuilder sb = new StringBuilder();
	    for (int i = 0; i < n; i++) {
	        int a = sc.nextInt();
	        long b = sc.nextInt();
	        int c = sc.nextInt();
	        if (c == 1) {
	            sb.append(-1).append("\n");
	        } else {
	            sb.append(getCount(a, c) * b).append("\n");
	        }
	    }
	    System.out.print(sb);
	}
	
	static int getCount(int x, int y) {
	    if (x == 0) {
	        return 0;
	    } else if (x % y == 0) {
	        return getCount(x / y, y) + 1;
	    } else if ((y - 1) * 2 >= x) {
	        return 2;
	    } else {
	        return getCount(x - x % y, y) + 1;
	    }
	}
}