SOLUTION: Peggy competes in a biathlon by running and bicycling around a large loop through a city. She runs the loop one time and bicycles the loop five times. She can run 8 mph and she can

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Peggy competes in a biathlon by running and bicycling around a large loop through a city. She runs the loop one time and bicycles the loop five times. She can run 8 mph and she can      Log On


   



Question 1009262: Peggy competes in a biathlon by running and bicycling around a large loop through a city. She runs the loop one time and bicycles the loop five times. She can run 8 mph and she can ride 16 mph. If the total time it takes her to complete the race is 1 hr 45 min, determine the distance of the loop.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = time in hrs for her to bicycle
5 times around the loop
+1.75+-+t+ = time in hrs for her to
run around loop 1 time
Let +d+ = the distance of the loop in miles
-------------------------------------
Her equation for running:
(1) +d+=+8%2A%28+1.75+-+t+%29+
Her equation for bicycling:
(2) +5d+=+16t+
---------------------
(1) +d+=+14+-+8t+
Substitute (1) into (2)
(2) +5%2A%28+14+-+8t+%29+=+16t+
(2) +70+-+40t+=+16t+
(2) +56t+=+70+
(2) +t+=+1.25+
-----------------
(2) +5d+=+16t+
(2) +5d+=+16%2A1.25+
(2) +5d+=+20+
(2) +d+=+4+
The distance of the loop is 4 mi
check:
(1) +d+=+8%2A%28+1.75+-+t+%29+
(1) +d+=+8%2A%28+1.75+-1.25+%29+
(1) +d+=+8%2A.5+
(1) +d+=+4+
OK