The language of oh yea doesn't exist :)
        
             
        
        
        
The problem simplified is 36√ 2abc
        
             
        
        
        
Answer:
Age of Mark  years
 years
Age of Mark's dad  years
 years
Age of Mark's sister  years
 years
Step-by-step explanation:
Let age of Mark be  years.
 years.
Mark's dad is three times older than Mark
Age of her Mark's dad 
Mark's sister is 2 years younger than Mark
Age of Mark's sister  years
 years
The sum of their ages is 48. 

Age of Mark  years
 years
Age of Mark's dad  years
 years
Age of Mark's sister  years
 years
 
        
             
        
        
        
To figure this out, you need to figure out what percentage 68 is of 85.
1. Divide 68 by 85 (Divide the % correct by the total number of questions)
2. 68/85 is .8, which is 80%