question: Jeff is 10 years older than his younger sister, Martha. Martha, on the other hand, is 4 years younger than her boyfriend, Mike. If Mike is 24 years old, how old is Jeff?
answer: Martha is 24 - 4 = <<24-4=20>>20 years old.
  Jeff is 20 + 10 =<<20+10=30>>30 years old.
  #### 30