SOLUTION: suppose you have entered a 121-mile biathlon that consists of a run and bicycle race. During your run, your average velocity is 6 miles per hours, and during your bicycle race, you

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Question 880936: suppose you have entered a 121-mile biathlon that consists of a run and bicycle race. During your run, your average velocity is 6 miles per hours, and during your bicycle race, your average velocity is 23 miles per hour. You finish the race in 6 hours. What is the distance of the run? What is the distance of the bicycle race?
Found 2 solutions by lwsshak3, josmiceli:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
suppose you have entered a 121-mile biathlon that consists of a run and bicycle race. During your run, your average velocity is 6 miles per hours, and during your bicycle race, your average velocity is 23 miles per hour. You finish the race in 6 hours. What is the distance of the run? What is the distance of the bicycle race?
***
let x=distance of the running race
121-x=distance of the bicycle race
travel time=distance/velocity
..
x%2F6%2B%28121-x%29%2F23=6
lcd=6*23=138
23x+6(121-x)=6*138
23x+726-6x=828
17x=102
x=6
121-x=115
distance of the running race = 6 miles
distance of the bicycle race=115 miles

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = the distance in miles for the run
+121+-+d+ = the distance in miles for the bicycle race
Let +t+ = the time in hrs for the run
+6+-+t+ = the time in hrs for the bicycle race
------------------------------------------
Equation for the run:
(1) +d+=+6t+
Equation for the bicycle race:
(2) +121+-+d+=+23%2A%28+6+-+t+%29++
---------------------------
(2) +121+-+d+=+23%2A6+-+23t+
(2) +121+-+d+=+138+-+23t+
(2) +23t+-+d+=+138+-+121+
(2) +23t+-+d+=+17+
Substitute (1) into (2)
(2) +23t+-+6t+=+17+
(2) +17t+=+17+
(2) +t+=+1+
--------------
Substitute this result back into (1)
(1) +d+=+6t+
(1) +d+=+6%2A1+
(1) +d+=+6+
and
+121+-+6+=+115+
The bicycle race is 115 mi
check:
(2) +121+-+d+=+23%2A%28+6+-+t+%29++
(2) +121+-+6+=+23%2A%28+6+-+1+%29++
(2) +115+=+23%2A5+
(2) +115+=+115+
OK