One hour after Yolanda started walking from X to Y, a distance of 80 miles, Bob started walking along the same road from Y to X. If Yolandaâs walking rate was 8 miles per hour and Bobâs was 9 miles per hour, how many miles had Bob walked when they met?
Select the correct option.
A) 38.07 B) 40 C) 42 D) 39 E) 40.07
Let t be the number of hours that Bob had walked when he met Yolanda. Then, when they met, Bob had walked 4t miles and Yolanda had walked 8(t + 1) miles. These distances must sum to 80 miles, so 9t + 8(t + 1) = 80, which may be solved for t as follows   9t + 8(t + 1) = 80   9t + 8t + 8 = 80   17t = 72   T = 4.23 (hours)   Therefore, Bob had walked 9t = 9(4.23) = 38.07 miles when they met. The best answer is 38.07.
<result>A</result>
One hour after Yolanda started walking from X to Y, a distance of 80 miles, Bob started walking along the same road from Y to X. If Yolandaâs walking rate was 8 miles per hour and Bobâs was 9 miles per hour, how many miles had Bob walked when they met?