Courier Express

#include <iostream>
#include <string>
#include <iomanip>

using namespace std;

int main() {
    double weight;
    cin >> weight;

    string service;
    cin >> service;

    int distance;
    cin >> distance;

    double standardPrice = 0;

    if (weight < 1) {
        standardPrice = 0.03;
    }
    else if (weight >= 1 && weight < 10) {
        standardPrice = 0.05;
    }
    else if (weight >= 10 && weight < 40) {
        standardPrice = 0.10;
    }
    else if (weight >= 40 && weight < 90) {
        standardPrice = 0.15;
    }
    else if (weight >= 90 && weight < 150) {
        standardPrice = 0.20;
    }

    double expressPrice = 0;

    if (service == "express") {
        if (weight < 1) {
            expressPrice = standardPrice * 0.80;
        }
        else if (weight >= 1 && weight < 10) {
            expressPrice = standardPrice * 0.40;
        }
        else if (weight >= 10 && weight < 40) {
            expressPrice = standardPrice * 0.05;
        }
        else if (weight >= 40 && weight < 90) {
            expressPrice = standardPrice * 0.02;
        }
        else if (weight >= 90 && weight < 150) {
            expressPrice = standardPrice * 0.01;
        }
    }

    double totalPrice = standardPrice * distance + expressPrice * distance * weight;

    cout << "The delivery of your shipment with weight of "
        << fixed << setprecision(3) << weight << " kg.would cost "
        << setprecision(2) << totalPrice << " lv." << endl;

    return 0;
}

Решение с тернарен оператор и printf():

#include <iostream>
#include <string>

using namespace std;

int main() {
    double weight;
    cin >> weight;

    string service;
    cin >> service;

    int distance;
    cin >> distance;

    double standardPrice =
        weight < 1 ? 0.03 :
        weight < 10 ? 0.05 :
        weight < 40 ? 0.10 :
        weight < 90 ? 0.15 :
        weight < 150 ? 0.20 : 0;

    double expressPrice = 0;

    if (service == "express") {
        expressPrice = 1 *
            (weight < 1 ? 0.80 :
            weight < 10 ? 0.40 :
            weight < 40 ? 0.05 :
            weight < 90 ? 0.02 :
            weight < 150 ? 0.01 : 0) * standardPrice * weight;
    }

    double totalPrice = (standardPrice + expressPrice) * distance;

    printf("The delivery of your shipment with weight of %.3f kg. would cost %.2f lv.\n", weight, totalPrice);

    return 0;
}