Fred and Sam are standing 100 miles apart and they start walking in a straight line toward each other at the same time. If Fred walks at a constant speed of 5 miles per hour and Sam walks at a constant speed of 5 miles per hour, how many miles has Sam walked when they meet? Choose one: A) 5 B) 9 C) 25 D) 30 E) 75
relative distance =100 miles   relative speed =5+5= 
<gadget id="calculator">5+5</gadget>
<output>10</output>
10 miles per hour   time taken=100/10=15 hours   distance travelled by sam =15*5= 
<gadget id="calculator">15*5</gadget>
<output>75</output>
75 miles=75
<result>E</result>
Fred and Sam are standing 100 miles apart and they start walking in a straight line toward each other at the same time. If Fred walks at a constant speed of 5 miles per hour and Sam walks at a constant speed of 5 miles per hour, how many miles has Sam walked when they meet?