Pagination on Angular JS 2

In this example i am using the Promise, but should be very slimier for Observables. 

This is my service look likes.

import { Injectable }    from '@angular/core';
import { Headers, Http, RequestOptions, Response } from '@angular/http';

import 'rxjs/add/operator/toPromise';

import {
    PaginatedResult,
    IQuestion,
    IServerResponse,
    ServerResponse
} from './../models/interfaces';

import { HttpClient } from './../common/http.client';

@Injectable()
export class QuestionService {
    private apiUrl = 'MyAPI/Questions';
    private http;

    constructor(private httpClient: HttpClient) {
        this.http = httpClient;
    }

    getPaged(searchTerm?: string, page?: number, pageSize?: number): Promise<PaginatedResult<IQuestion[]>> {
        return this.http.get(this.apiUrl + "?page=" + page + "&pageSize=" + pageSize + "&searchTerm=" + searchTerm)
            .toPromise()
            .then(response => response.json() as PaginatedResult<IQuestion[]>)
            .catch(this.handleError);
    }

    private handleError(error: any) {
        // show the error
        return Promise.reject(new ServerResponse(error.status, error.statusText, error.ok, error._body));
    }
}