Niko will earn $2 x 25/100 = $<<2*25/100=0.5>>0.5 profit for each of the first four pairs of socks.
So, his total profit for the four pairs of socks will be $0.5 x 4 = $<<0.5*4=2>>2.
His total earnings for the 5 pairs of socks is $0.2 x 5 = $<<0.2*5=1>>1.
Therefore, his total profit will be $2 + $1 = $<<2+1=3>>3.
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