Roberto plans to use two transformers to reduce a voltage of 120 v to 4 v. he uses a transformer that has 300 coils in the
primary winding and 50 coils in the secondary winding. he has four other transformers, as listed in the table.
transformer
secondary winding (coils)
primary winding (coils)
80
60
70
50
to
which transformer should roberto use to have an ending voltage of 4 v?