>>471
int main(){
DWORD price_A = 148000,price_B = 99800,price_C = 44200;
DWORD day_A = 13,day_B = 20,day_C = 34;
//まずはAとBの比較
DWORD price_diff = price_A - price_B;
DWORD day_diff = day_B - day_A;
DWORD day = price_diff / day_diff + 1;
printf("%d日でA = %d円 B = %d円\n",day,price_A+day_A*day,price_B+day_B*day);
//次にAとCの比較
price_diff = price_A - price_C;
day_diff = day_C - day_A;
day = price_diff / day_diff + 1;
printf("%d日でA = %d円 C = %d円\n",day,price_A+day_A*day,price_C+day_C*day);
}