Incorrect. Use the formula $\displaystyle{d}={r}{t}\usepackage{cmbright}\Huge\$ to represent both legs of the journey:

	Distance	=	Rate	*	Time
Outgoing	d	=	r	*	1
Incoming	d	=		*	0.75

The distance, d, is the same in both trips because she took the same path home as she did on the way out.

Think about the rate for her outgoing and incoming trips. If you represent her rate as r on the way out, how do you represent the idea of "4 miles per hour faster going home"? Which system represents the rates of the different parts of her trip correctly?