2063: [example 1.4] cattle eat grass

2063：【 example 1.4】 Cattle eat grass

The time limit : 1000 ms         Memory limit : 65536 KB
Submission number : 27604     Passing number : 16637

【 Title Description 】
There's a ranch , The grass on the pasture grows at a constant speed every day , This pasture is available for 15 Cattle to eat 20 God , Or available 20 Cattle to eat 10 God , that , The amount of grass that grows in this pasture every day can feed several cows 1 God ？

【 Input 】
（ nothing ）

【 Output 】
As stated in the title , The number of cattle .

【 sample input 】
（ nothing ）
【 sample output 】
（ nothing ）
 

#include<iostream>
using namespace std;
int main()
{
	int num, sum,v,m;//v Is the daily growth ,m It's the amount each cow eats 
	num = (15*20-20 * 10) / (20 - 10);
	cout << num;
	return 0;
 
}