Yes, it is possible if you start to take the right classes early and are prepared to work hard.
Any degree required a core set of classes, like english, math, etc. Once you get through those you work on your major classes. If the 2 major's are similar enough not to give you two different work loads then it's easier. But if the 2 majors are completely different then it will take a lot more time.
Note that many people don't finish Bachelor's degrees in 4 years any more. It is closer to 5 years for some.