Verified Answer :

toporc

First add the given ratio numbers, as follows:
2 + 4 = 6
The left hand number of the required ratio is given by:
\(\frac{2}{6}\times 30=10\)
The right hand number of the required ratio is given by:
\(\frac{4}{6}\times30=20\)
The required ratio is 10 : 20