Current Electricity

A galvanometer has resistance '\(\mathrm{G}\)' \(\Omega\) and '\(\mathrm{I}_{\mathrm{g}}\)' is current flowing through it which produces full scale deflection. '\(\mathrm{S}_1\)' is the value of shunt which converts it into an ammeter of range 0 to '\(3 \mathrm{I}\)' and '\(\mathrm{S}_2\)' is the shunt value which converts it into an ammeter of range 0 to '\(4 \mathrm{I}\)', the ratio \(\mathrm{S}_2: \mathrm{S}_1\) is