Well, for his you would have to find the unit rate.
The easiest way to do this would first be converting 3/5 into a fraction (0.6)
next, divide that by 4 to get the weight of 1.
0.6/4 (the same as 0.6 x 0.25 or 6/10 x 1/4 if you are doing it without a calculator)
each bread weighs 3/20 (or 0.15) pounds.