Geocoding API returns different results than the sample app

When I make a request using this address: http://open.mapquestapi.com/geocoding/v1/address?key=KEY&inFormat=kvp&ou...

I got the following coordinates:

"lat": 39.78373, "lng": -100.445882

and when I make the same request using the live sample site (https://developer.mapquest.com/documentation/samples/geocoding/v1/address/) I get:

"lat": 40.70746,"lng": -74.00432

Which is correct.

Is there something that I'm missing?.

Please help.

Thanks!