if statements in C programming

#include <stdio.h>
#define TAX_RATE 0.065

int main () {
   
    double cost;
    int quantity, taxed, weight, cost_with_shipping;
   
    printf("What is the cost of the item to be purchased (in dollars)?\n");
    scanf("%lf", &cost);
    printf("What is te weight of the item (in pounds)?\n");
    scanf("%d", & weight);
    printf("How many of the item are you purchasing?\n");
    scanf("%d", &quantity);
    printf("Is the item a taxed item (1 = yes, 0 = no)?\n");
    scanf("%d", & taxed);
       
    if (weight > 0 && weight <= 10);
    cost_with_shipping = (weight * 4) + cost;
    double total_cost = cost_with_shipping*quantity*(1+ taxed*TAX_RATE);   
    printf("Your total purchase, with shipping, will cost $%.21f.\n", total_cost);
   
    else (weight > 10 && weight <= 30);
    cost_with_shipping = (weight * 2.5) + cost;
    double total_cost = cost_with_shipping*quantity*(1+ taxed*TAX_RATE);
    printf("Your total purchase, with shipping, will cost $%.21f.\n", total_cost);
   
    else (weight > 30 && weight <= 50);
    cost_with_shipping = (weight * 1.5) + cost;
    double total_cost = cost_with_shipping*quantity*(1+ taxed*TAX_RATE);
    printf("Your total purchase, with shipping, will cost $%.21f.\n", total_cost);
   
    else (weight > 50);
    cost_with_shipping = (weight * .99) + cost;
    double total_cost = cost_with_shipping*quantity*(1+ taxed*TAX_RATE);
    printf("Your total purchase, with shipping, will cost $%.21f.\n", total_cost);
   
    system("PAUSE");
    return 0;
}