One hour after Yolanda started walking from X to Y, a distance of 17 miles, Bob started walking along the same road from Y to X. If Yolanda's walking rate was 3 miles per hour and Bobт's was 4 miles per hour, how many miles had Bob walked when they met?
Choose the correct choice from the following options:  A) 24  B) 23  C) 22  D) 21  E) 8
When B started walking Y already has covered 3 miles out of 17, hence the distance at that time between them was   17-3= 
<gadget id="calculator">  17-3</gadget>
<output>14</output>
14 miles.   Combined rate of B and Y was   3+4= 
<gadget id="calculator">  3+4</gadget>
<output>7</output>
7 miles per hour, hence they would meet each other in  14/7= 
<gadget id="calculator"> 14/7</gadget>
<output>2</output>
2 hours. In 6 hours B walked  2*4= 
<gadget id="calculator"> 2*4</gadget>
<output>8</output>
8 miles.   Answer: 8.
<result>E</result>
One hour after Yolanda started walking from X to Y, a distance of 17 miles, Bob started walking along the same road from Y to X. If Yolanda's walking rate was 3 miles per hour and Bobт's was 4 miles per hour, how many miles had Bob walked when they met?