Taking the distance as d, we have that:
In this equation, it is expressed that he ran half the distance which is 1/2d, he swam a quarter of the distance, which is 1/4d and the remaining is xd, which is how far did he ride the bike (14 miles). Solve the equation for x:
It means that he ride the bike a quarter of the distance. We know that he ride the bike 14 miles, which means that 14 miles is a quarter of the distance, using this information we can find the total distance of the race: