3 min of right clock = $(3 + \frac{1}{12}) = \frac{37}{12}$ min of wrong clock
3/60 hr of right = 37/(12*60) hr of wrong
and wrong clock run 9hr 15 min from 7am to 4:15pm
so (9 + 15/60) = 37/4 hr of wrong = (3/60) * 3 * 60 = 9hr of right clock.
So right clock show 7am + 9hr = 4pm