Can someone please help me with Q9

Present age of man = 4x  years

After 16 years ,
Age of son = (x + 16) years
Age of man = (4x + 16) years

after 16 years ,
2× (age of son) = age of man
2(x + 16) = 4x + 16
2x + 32 =  4x + 16
2x = 32-16 = 16
=>   x = 8 
Hence , present age of son = 8 years

Present age of man = 4x = 32 years

Regards