Question 889871: Ironman Triathlon. Held annually in Hawaii since 1978, the Ironman Triathlon championship is a series of long-distance races consisting of a 2.4-mi swim, a 112-mi bicycle ride, and a 26.2-mi marathon. At one point, a participant had completed twice as many miles as the number of miles left to complete. How many miles had he completed at that mark?
140.6= x + 2x +
I'm confused on how the formula should be wrote.
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
I sincerely hope that you are actually confused about how the formula should be written.
Your representation, aside from the extraneous plus sign at the end, was a perfectly good mathematical model of the situation assuming you intended  to represent the distance remaining. The only difficulty with your method is that once you solve for , you have to multiply it by 2 in order to arrive at the answer to the question asked, namely "How many miles had he completed at that mark?"
In order to answer the question more directly, let represent the number of miles already traveled. Then the remaining distance is one half of that amount, hence:
And solving for gives you the answer to the question posed.
Alternatively, you could save yourself a good deal of angst by recognizing that he has completed 2 out of 3 parts of the race, hence he has gone 2/3 times 140.6 miles.
John
My calculator said it, I believe it, that settles it
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