Jen has a jar of jam, and she ate 1/3 of the jam for lunch. If Jen ate 1/7 of the remaining jam for dinner, what fraction of the jam was left after dinner?  Choose the most appropriate option:
A) 2 / 7 B) 3 / 7 C) 4 / 7 D) 9 / 14 E) 11 / 14

Rationale: let x be the amount of jam at the beginning . after lunch , the remaining jam was ( 2 / 3 ) x . after dinner , the remaining jam was ( 6 / 7 ) ( 2 / 3 ) x = ( 4 / 7 ) x . the answer is c .
Answer: C