The amplitude of a damped oscillator becomes half in one minute. The amplitude after 3 minute will be 1X times the original, where X is

Amplitude of damped oscillator A=A0e−λt; λ =constant, t = time For t =1 min.  A02=A0e−λt⇒eλ=2For t = 3 min.  A=A0e−λ×3=A0(eλ)3=A023⇒X=23