For someone who is more interested in applied mathematics than abstract, which degree should one pursue in order to have a career in applied mathematics, considering he/she has pursued an MS in abstract mathematics? Is it advisable, considering that the person does not know much of the basics of applied mathematics?
If you already have a Master's degree in mathematics, you should be capable of learning additional mathematics topics yourself. If you are interested in a particular field in which mathematics is applied, you can always spend some time becoming acquainted with that field and the mathematics involved. The Society for Industrial and Applied Mathematics (http://www.siam.org/) is one resource to get an idea of what's out there. You might look for a smallish project to test the water and pick up some experience in mathematical modeling and, if relevant, computational mathematics. Years ago as a student, I did a summer project on modeling measles epidemics using difference equations. It was a valuable experience and taught me more than merely reading about mathematical modeling in a book or on a website.
You may also wish to bear in mind that seemingly pure mathematics can often end up being very applicable, so you may be able to have the best of both worlds. For instance, Bernd Sturmfels has used algebraic geometry in statistics and computational biology and Robert Ghrist has applied algebraic topology to signal processing and sensor networks.