SOLUTION: Fred bicycles 6km/hr slower than Samantha. In the time it takes Fred to bicycle 52 km, Samantha travels 76 km. How fast does Fred bicycle? I understand what variables that I nee

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Question 967916: Fred bicycles 6km/hr slower than Samantha. In the time it takes Fred to bicycle 52 km, Samantha travels 76 km. How fast does Fred bicycle?
I understand what variables that I need to use, but I'm having troubles remembering what equation to put the variables into. If you could also explain how you got your answer that would be fantastic.
Thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = time in hrs that both spend biking
Let +s+ = Samantha's speed in km/hr
------------------------------------
Fred's equation:
(1) +52+=+%28+s+-+6+%29%2At+
Samantha's equation:
(2) +76+=+s%2At+
--------------------
(1) +52+=+s%2At+-+6t+
and
(2) +s+=+76%2Ft+
--------------------
Substitute (2) into (1)
(1) +52+=+76+-+6t+
(1) +6t+=+24+
(1) +t+=+4+
and
(2) +s+=+76%2F4+
(2) +s+=+19+
and
+s+-+6+=+13+
----------------
Fred bikes 13 km/hr
-------------------
check:
(1) +52+=+%28+s+-+6+%29%2At+
(1) +52+=+13%2At+
(1) +t+=+4+
OK