C :

#include<stdio.h>
void main()
{
	int n,i,money,num,x,ten,five,one;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		scanf("%d%d",&money,&num);
		if(num==1)
			x=money-4;
		if(num==2)
			x=money-3;
		if(num==3)
			x=money-1;
		ten=x/10;
		five=x%10;
		if(five>=5) {five=1;one=x%10-5;}
		else {five=0;one=x%10;}
		printf("%d\n",ten+five+one);
	}
}

C++ :

#include<stdio.h>
int main()
{
	int f[]={0,4,3,1};
	int T;
	scanf("%d",&T);
	while(T--)
	{
		int n,m;
		scanf("%d%d",&n,&m);
		n-=f[m];
		int count=0;
		count+=n/10;
		count+=n%10/5;
		count+=n%10%5;
		printf("%d\n",count);
	}
}