Answer:
Fire hydrant with a purple cap (with respect to a fire hydrant with a green cap):
![\dot Q_(purple) = (1)/(2)\cdot \dot Q_(green)](https://img.qammunity.org/2021/formulas/mathematics/college/a5urbj5zo6v5czkgit1ehf69wgnd0g5is0.png)
Explanation:
The volume rate of the fire hidrant with a purple cap is equal to the product of the proportion factor and the volume rate of the fire hydrant with a concrete cap.
![\dot Q_(i) = k \cdot \dot Q_(j)](https://img.qammunity.org/2021/formulas/mathematics/college/hb78jww86ssxjtixm3pyzd4sh398awqtyu.png)
There are two different solutions:
Fire hydrant with a purple cap (with respect to a fire hydrant with a green cap):
![\dot Q_(purple) = (1)/(2)\cdot \dot Q_(green)](https://img.qammunity.org/2021/formulas/mathematics/college/a5urbj5zo6v5czkgit1ehf69wgnd0g5is0.png)
Fire hydrant with a purple cap (with respect to a fire hydrant with a blue cap):
![\dot Q_(purple) = (1)/(2) * (1000\,gpm)/(1500\,gpm)\cdot \dot Q_(blue)](https://img.qammunity.org/2021/formulas/mathematics/college/1m3r3fdg80m84h5h0m9a0e0tzl1ofj04wu.png)
![\dot Q_(purple) = (1)/(3)\cdot \dot Q_(blue)](https://img.qammunity.org/2021/formulas/mathematics/college/v6xakxa37070dbgky50336fi861fnxxqt1.png)