HW problem, don't know how to proceed

[Meezy111]

I'm doing this for HW and I don't really know what to do now, there is also a menu function and a file input function. Can someone help me?


Linda is starting a new cosmetic and clothing business and would like to
make a net profit of approximately 10% after paying all the expenses, which
include merchandise cost, store rent, employees’ salary, and electricity cost
for the store. She would like to know how much the merchandise should be
marked up so that after paying all the expenses at the end of the year she gets
approximately 10% net profit on the merchandise cost. Note that after
marking up the price of an item she would like to put the item on 15% sale.
Write a program that prompts Linda to enter the total cost of the merchandise, the salary of the employees (including her own salary), the yearly rent,
and the estimated electricity cost. The program then outputs how much the
merchandise should be marked up so that Linda gets the desired profit

  #include <iostream>
using namespace std;

int main()
{
	const double PROFIT_PERCENT = 0.01;
	double cost_merchandise, salary, yearly_rent, total_expense, tenpercentprofit, electricity_cost;
	double totalCost, netProfit;
	
	cout << "Enter merchandise cost: ";
    cin >> cost_merchandise;

    cout << "Enter employee salary: ";
    cin >> salary;

    cout << "Enter yearly rent: ";
    cin >> yearly_rent;

    cout << "Enter the estimated electricity cost: ";
    cin >> electricity_cost;

    totalCost = cost_merchandise + salary + yearly_rent +electricity_cost;
    netProfit = totalCost * PROFIT_PERCENT;
    
    return 0; 
}

[Thomas1965]

What did you input?
What was the output?
What was the supposed output?

[Enoizat]

a file input function

I there a set of data you are expected to use? Can you give us at least an example?
What's more, the question doesn't sound clear to me. For example, if Linda estimates to spend, let's say $ 1,000.00 a year for electricity, which percentage of its cost should be charged on every garment? I think it should be different if she anticipates to sell 10,000 pairs of trousers or 100,000 of them, doesn't it?
Didn't your teacher give you any hint?