Joan and Karl each bought a sofa and the sum of their purchases was $600. If twice of what Joan paid was $90 more than what Karl paid, what did Joan pay for her sofa?
Options:
A) $ 190
B) $ 210
C) $ 230
D) $ 250
E) $ 270

Rationale: j + k = 600 so k = 600 - j 2 j = k + 90 2 j = ( 600 - j ) + 90 3 j = 690 j = 230 the answer is c .
Answer: C