solution of above question....

#include<iostream>
using namespace std;
int main()
{
double milage,price,pricemorethan100,rate,milagemorethan100;
cout<<"Enter the Milage = ";
cin>>milage;
if(milage<=100)
{
price = milage * 0.25;
cout<<"The Gasolone bill is = $ "<<price<<endl;
}
else if(milage>100)
{
milagemorethan100 = milage - 100;
pricemorethan100 = milagemorethan100 * 0.15;
price = 100 * 0.25;
rate = price + pricemorethan100;
cout<<"The gasoline bill is = $ "<<rate<<endl;
}
return 0;
}
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 Q # 2: Find maximum of three numbers...

The solution is:

#include<iostream>
using namespace std;
int main()
{
int n1,n2,n3;
cout<<"Enter three Numbers ";
cin>>n1>>n2>>n3;
if(n1 > n2 && n1 > n3)
{
cout<<" Number1 is Maximum"<<endl;
}
else if(n2 > n1 && n2 > n3)
{
cout<<" Number2 is Maximum"<<endl;
}
else if(n3 > n2 && n3 > n1)
{
cout<<"Number3 is Maximum"<<endl;
}
else if(n1==n2 && n1>n3)
{
cout<<"number 1 and number 2 are equal but greater than number3."<<endl;
}
else if(n2==n3 && n2>n1)
{
cout<<"number 2 and number 3 are equal but greater than number1."<<endl;
}
else if(n3==n1 && n3>n2)
{
cout<<"number 1 and number 3 are equal but greater than number2."<<endl;
}
else
{
cout<<"all three numbers are equal"<<endl;
}
return 0;
}
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Q # 3: Make a basic calculator using else if:
 
Solution:
 
#include<iostream>
using namespace std;
int main()
{
    int n1,n2;
    char operation;
    cout<<"Enter two numbers";
    cin>>n1>>n2;
    cout<<"Enter Operation = ";
    cin>>operation;
    if(operation=='+')
    {
    cout<"Addition"<<n1+n2<<endl;
    }
    else if(operation=='-')
    {
    cout<<"Subtraction"<<n1-n2<<endl;
    }
    else if(operation=='*')
    {
    cout<<"Multiplication"<<n1*n2<<endl;
    }
    else if(operation=='/')
    {
    cout<<"Division"<<static_cast<double>(n1) / (n2)<<endl;
    }
    else if(operation=='%')
    {
    cout<<"Modulus"<<n1%n2<<endl;
    }
    else    cout<<"Invalid Value"<<endl;
return 0;
}