Question: When Saginaw's fare is $470.47, what was the fare to Grand Rapids?
Schema: create table table_1637981_7 (grand_rapids__grr_ varchar, saginaw__mbs_ varchar, PRIMARY KEY (grand_rapids__grr_))
SQL: select grand_rapids__grr_ from table_1637981_7 where saginaw__mbs_ = "$470.47"