The marks obtained by Polly and Sandy are in the ratio 5:6 and those obtained by Sandy and Willy are in the ratio of 9:7. The marks obtained by Polly and Willy are in the ratio of...?	Choose the correct choice from the following answers:
A) 9 : 8 B) 11 : 10 C) 13 : 12 D) 15 : 14 E) 17 : 16

Rationale: polly : sandy = 5 : 6 = 15 : 18 sandy : willy = 9 : 7 = 18 : 14 polly : sandy : willy = 15 : 18 : 14 polly : willy = 15 : 14 the answer is d .
Answer: D