Subject: mathqa
Question: an investor can sell her microtron stock for 36 $ per share and her dynaco stock for 68 $ per share , if she sells 300 shares altogether , some of each stock , at an average price per share of 40 $ , how many shares of dynaco stock has she sold ?
Option: 
A: 136
B: 52
C: 37.5
D: 184
Answer: C