Do this solution using time quantities and change to time line later.
JOB/HOURS
WADE
SARAH
BOTH
The two periods of time are 2 hour and unknown t hours.
Those correspond to just Wade alone, and Wade plus Sarah.
Uniform Work Rates Rule is RT=J to relate rate, time, and amount of job or jobs. The ONE job to be done is "clean the house".
------------Forming this equation is the most important part of the solution. Solving for t is the easy part. t is not "what time"; but it is "how much time".