Problem $2UG-$ Gini Index. $[25]$;$\{4/5\}$ respect to GINI?

The results for the following intermediate steps trust be given:

Parent measure $[4],$

For each choice of a split $[20]$

i$.$ measure for each child,

ii$.$ Combined children measure,

iii. Gain.

Final result $[1]$

Hint: Think of how many alternative binary splits make sense if we assume that income is a meaningful attribute for the decision. Is income a nominal, ordinal or interval attribute here?