Explanation: ধরি, এখন Jim এর বয়স J, Fred এর F এবং Sam এর S\n\(\therefore F = J/2\) এবং \(F = S+2\)\n\(\Rightarrow J/2 = S+2 \Rightarrow S = J/2 - 2\)\n4 years আগে, \(J-4 = 4(S-4) \Rightarrow J-4 = 4S-16\)\n\(\Rightarrow J-4 = 4(J/2 - 2) - 16\)\n\(\Rightarrow J-4 = 2J - 8 - 16 \Rightarrow J-4 = 2J - 24 \Rightarrow J = 20\)
