Four friends built a colony for themselves. They built their own houses at different distances from each other.
Chris lived 60 km away from Alex.
Darren lived 40 km away from Bill.
Chris lived 10 km nearer to Darren than he lived to Bill.
Can you find out how far was Darren's house from Alex?  Choose the most appropriate option.
A) 55 km. B) 65 km. C) 75 km. D) 85 km. E) 95 km.
Solution:   75km   Explanation:   Distance between Bill and Darren = 40 km   Distance between Bill and Chris + Distance between Chris and Darren = 40 km   Distance between Bill and Chris + (Distance between Bill and Chris - 10) = 40 km   2 * Distance between Bill and Chris = 50 km   Distance between Bill and Chris = 25   Distance between Chris and Darren = 15 km   Therefore, distance between Darren's house and Alex's house = 60 + 15= 
<gadget id="calculator">60 + 15</gadget>
<output>75</output>
75 km.   Answer 75 km.
<result>C</result>
Four friends built a colony for themselves. They built their own houses at different distances from each other.
Chris lived 60 km away from Alex.
Darren lived 40 km away from Bill.
Chris lived 10 km nearer to Darren than he lived to Bill.
Can you find out how far was Darren's house from Alex?