求助，C语言#9无法通过

#include<stdio.h>
int main()
{
    int HH=7, MM=50;
    float s, v, t;
    scanf("%f %f", &s, &v);
    t = s / v;

    if (t != 0)/*用时不为0时*/
        MM = MM - (int)t - 1;

    /*时间转换*/
    while (MM >= 60)
    {
        HH++;
        MM -= 60;
    }
    while (MM < 0)
    {
        HH--;
        MM += 60;
    }

    /*跨天转换*/
    if (HH < 0)
    {
        HH = 24 + HH;
    }
    if (HH >= 24)
    {
        HH = 24 - HH;
    }

    /*输出*/
    if (HH < 10)
        printf("0");
    printf("%d:", HH);
    if (MM < 10)
        printf("0");
    printf("%d", MM);

    return 0;
}