To determine how long it will take for Andy to row half a mile farther than Sal, we can set up an equation based on the rates at which they are rowing and the distance. Let's call the time it takes Andy to row half a mile farther than Sal "t" (in hours).
Andy's rate is 6 mph, so in t hours, he will row a distance of 6t miles.
Sal's rate is 4 mph, so in t hours, he will row a distance of 4t miles.
Now, we want Andy to row half a mile farther than Sal. Therefore, the distance Andy rows (6t) should be half a mile more than the distance Sal rows (4t). We can set up the equation:
6t = 4t + 0.5
Now, let's solve for t:
2t = 0.5
To isolate t, divide both sides by 2:
t = 0.5 / 2
t = 0.25
So, it will take Andy 0.25 hours (or 15 minutes) to row half a mile farther than Sal.