I encountered this issue solving a competitive programming challenge [Easy]

Given a number of workers ‘x’ that need ‘d’ days to a work to be done:

what are the amount of days less if are added ‘y’ workers?

int main(){

// ((d / x) * y) != ((x * p)/(x + y)) * y) ?

return 0;
}

I use Visual Studio.

I tried this formula ((d / x) * y) did not worked.

then I tried this ((x * p)/(x + y)) * y)

and result is different and I don’t understand why… and aso give an error.

Can someone explain me why two formulas are not equal?

I used all kind of precision data and I need an integer (less than 1 day is 0).
I also tried: if(result < 0){result = d;} …