```
#include<stdio.h>
int main()
{
double s, v;
scanf("%lf %lf", &s, &v);
double t = s / v + 10;
int H = 8, i = 0, M;
while (t > 0) {
t = t - 1;
i ++;
}
if (i == 0)
printf("08:00");
else if (i > 0 && i <= 480) {
H = H - 1;
M = 60 - i;
while (M < 0) {
H = H - 1;
M = 60 + M;
}
if (M >= 10)
printf("0%d:%d", H, M);
else
printf("0%d:0%d", H, M);
} else if (i > 480 && i <= 1320) {
H = 24;
i = i - 480;
H = H - 1;
M = 60 - i;
while (M < 0) {
H = H - 1;
M = 60 + M;
}
if (M >= 10)
printf("%d:%d", H, M);
else
printf("%d:0%d", H, M);
} else if (i > 1320 && i <= 1440) {
H = 24;
i = i - 480;
H = H - 1;
M = 60 - i;
while (M < 0) {
H = H - 1;
M = 60 + M;
}
if (M >= 10) printf("0%d:%d", H, M);
else printf("%0d:0%d", H, M);
}
}
```
by IDNo1 @ 2023-01-14 17:23:58
@[fangshi](/user/740350) 第一，可能比七点更早。第二，如果a是b的倍数，不需要+1
by smallpeter @ 2023-01-14 17:25:25