A 50 year old person would typically display have higher CRYSTALLIZED INTELLIGENCE but lower FLUID INTELLIGENCE than a 25 year old person.
Crystallized intelligence refers to one's ability to utilize skills, experience and knowledge. It involves recalling information from long term memory. Fluid intelligence on the other hand refers to one's ability to think abstractly, solve problems, identify patterns, etc. Fluid intelligence is normally used by psychologists to determine level of intelligence.