Question

what was the rate of interest on which shylock gave bassanio
3 thousand ducats

Answer 1

Actually there was no rate of interest on which Shylock gave Bassanio three thousand ducats. Shylock gave three thousand ducats to  Bassanio on the condition that if Bassanio was not able to repay the money within three months then Shylock would extract a pound of flesh from Antonio's body.