$10+10+10=30$ 
There are some ducks and sheep in a farm. The number of sheep is $10$ more than ducks. The number of ducks is half the number of sheep. In total, how many ducks and sheep are there in the farm?  ~ 
Options:
  $26$ 
  $$30$$ 
  $$33$$ 
  $$39$$ 
  $$40$$ 