Respuesta :

chikafujiwara

1.5x + 2.25x + 3.375x + n * x

OR

7.12500x + (n * x)

Explanation :

1.5x, 2.25x, and 3.375x are given.

Since we don't know how much Gavin rode on the fourth day, we can say that it is n * x since it is an unknown.