Let Liam's age= x
Max's age= 25
After two years Max's age= 25+2
After two years Liam's age= x+2
After two years Liam will be half of MAx's age,
So-

Liam's age after 2 years= 11.5 + 2= 13.5
Max's age after 2 years - 27
13.5 is half of 27 answer
Hope I helped~!