a guy was asked to specify his age in years . he said , “ take my age 5 years hence , multiply it by 5 and subtract 5 times of my age 5 years ago and you will know my age . ” what was the age of that guy ?
Choices: A) 18 B) 15 C) 33 D) 39 E) 50

Rationale: current age of the guy = a years . then , 5 ( a + 5 ) – 5 ( a – 5 ) = a ( 5 a + 25 ) – ( 5 a – 25 ) = a a = 50 e
Answer: E