C++ :

#include <iostream>
using namespace std;

int main(){
	int max = 30 * 1200;
	int p = 30;
	int c = 1200;
	int s;//售价 
	int n;
	cin>>n;
	int price = p;//假设p元最划算 
	while(c > 0){
		p++;
		c -= n;//每加1元，数量减少n张
		s = p * c;
//		cout<<p<<" "<<c<<" "<<s<<endl; 
        if(s > max){
        	max = s;
        	price = p;
		}
	}
	cout<<price<<" "<<max<<endl;
} 

Python :

n = int(input())
x = 30
y = 1200
j = []
m = []
while(x <= y):
    z = x * y
    j.append(z)
    if(max(j) == x * y):
        m.append(x)
    x += 1
    y -= n
print(max(m), max(j))