15x^2y^4z / 3xy^5

To simplify the expression (15x^2y^4z) / (3xy^5), we can divide the coefficients and then divide the variables.

Dividing the coefficients:
15 / 3 = 5

Dividing the x variables:
x^2 / x = x^(2-1) = x^1 = x

Dividing the y variables:
y^4 / y^5 = y^(4-5) = y^(-1) = 1/y

Putting it all together, the simplified expression is:
5xz / y