Question

An ironman triathlon requires each participant to swim 1.2 miles down a river, turn

at a marked buoy, then swim 1.2 miles back upstream. A certain participant is
known to swim at a pace of 2 miles per hour and had a total swim time of 1.25
hours. How fast was the river's current?
PLEASE HELP!!! THIS IS DUE AT MIDNIGHT!!!

Answer 1

To solve the problem, we can use the formula:

Total swim time = (time swimming downstream) + (time swimming upstream)

Let's call the speed of the river's current "c". When swimming downstream, the participant's effective speed is 2 + c miles per hour. When swimming upstream, the effective speed is 2 - c miles per hour.

Using the formula above and plugging in the given values, we get:

1.25 = (1.2 / (2 + c)) + (1.2 / (2 - c))

Simplifying this equation requires some algebraic manipulation, but we can eventually arrive at:

c^2 - 1.44 = 0

Solving for c gives us:

c = ±1.2

Since the participant is swimming both downstream and upstream, we know that the current must be flowing in one direction only. Therefore, we take only the positive solution:

The river's current is 1.2 miles per hour.