Ice cubes melt at temperature above 0 degree celsius.
Or ((2t^2)/(t+2) ) -4 =0
Or 2t^2 = 4t + 8 =0
Or 2t^2 - 4t -8 = 0
or t^2 -2t - 4 =0
On solving the following quadratic equation using Quadratic formula, t = -b +- sqrt(b^2 -4ac)/2a, we get:
t = 1 - sqrt(5) or t = 1 + sqrt(5)
Neglecting t = 1- sqrt(5) as time doesnot flow backward.
Therefore, the ice cubes will start melting at 4 + 1 + sqrt(5) = 5 + sqrt(5)
or it will start melting at 08: 14 : 10 pm