One hour after Yolanda started walking from X to Y, a distance of 60 miles, Bob started walking along the same road from Y to X. If Yolandaâs walking rate was 5 miles per hour and Bobâs was 6 miles per hour, how many miles had Bob walked when they met?	Choose the correct option.
A) 40
B) 25
C) 28
D) 30
E) 30.5

Rationale: "let t be the number of hours that bob had walked when he met yolanda . then , when they met , bob had walked 4 t miles and yolanda had walked 5 ( t + 1 ) miles . these distances must sum to 60 miles , so 6 t + 5 ( t + 1 ) = 60 , which may be solved for t as follows 6 t + 5 ( t + 1 ) = 60 6 t + 5 t + 5 = 60 11 t = 55 t = 5 ( hours ) therefore , bob had walked 6 t = 6 ( 5 ) = 30 miles when they met . the best answer is d ."
Answer: D