Lionel left his house and walked towards Walt's house, 48 miles away. Two hours later, Walt left his house and ran towards Lionel's house. If Lionel's speed was 3 miles per hour and Walt's 4 miles per hour, how many miles had Lionel walked when he met Walt?  Choose the correct choice:
A) 12
B) 16
C) 20
D) 24
E) 28
In the first 2 hours Lionel at the rate of 3 miles per hour covered distance=rate*time=3*2= 
<gadget id="calculator">3*2</gadget>
<output>6</output>
6 miles. So, the distance between him and Walt was 48-6= 
<gadget id="calculator">48-6</gadget>
<output>42</output>
42 miles when Walt left his house. Now, their combined rate to cover this distance was 3+4= 
<gadget id="calculator">3+4</gadget>
<output>7</output>
7 miles per hour, hence they will meet (they will cover that distance) in time=distance/rate=42/7= 
<gadget id="calculator">42/7</gadget>
<output>6</output>
6 hours. Total time that Lionel was walking is 2+6= 
<gadget id="calculator">2+6</gadget>
<output>8</output>
8 hours, which means that he covered in that time interval distance=rate*time=3*8= 
<gadget id="calculator">3*8</gadget>
<output>24</output>
24 miles.   Answer: 24.
<result>D</result>
Lionel left his house and walked towards Walt's house, 48 miles away. Two hours later, Walt left his house and ran towards Lionel's house. If Lionel's speed was 3 miles per hour and Walt's 4 miles per hour, how many miles had Lionel walked when he met Walt?