A movie buff buys movies on DVD and on Blu-ray in a ratio of 17:4. If she returns 4 Blu-ray movies, that ratio would change to 9:2. If she buys movies on no other medium, what was the original number of movies purchased?
Choose the correct answer.
A) 22  B) 28  C) 77  D) 99  E) 378

Rationale: if u can just keep an eye on the options 99 is the only multiple of 9 in options given . . so you can mark it wid in seconds . now coming to the process m ( d ) = 17 x and b ( d ) = 4 x now from the next line the new eqn becomes 17 x / ( 4 x - 4 ) = 9 / 2 solving it 34 x = 36 x - 36 x = 18 which means m ( d ) = 306 and b ( d ) = 72 so total initially is m ( d ) + b ( d ) = 378 e
Answer: E