$$5+3=8$$  $$7+3=10$$  $$10+8=18$$ 
SASMO 2015 P2 Q10  John is 5 years old this year. His sister is 2 years old. What is the sum of their age after 3 years? 
Options:
  $$18$$ 
  $$16$$ 
  $$14$$ 
  $$12$$ 
  $$10$$ 