$100 \div (3 + 1)~ \times 3= 75$ 
Mark and Karl have $$100$$ dollars in total. The money Mark owns is three times the money Karl owns. How many dollars does Mark have? (Adapted from 1999 Math Kangaroo Problem, Level 3 - 4, Question \#6) 
Options:
  * $$20$$ 
  * $$25$$ 
  * $$35$$ 
  * $$75$$ 
  * $$80$$ 