On the weekends, Eliza only reads romance novels  During the week, Eliza paints three days a week unless she has pressing family obligations or is substitute teaching at the local art school  Four days a week, Eliza practices her cello, and on Wednesdays, she gives cello lessons  Last week, Eliza had no pressing family obligations, nor did she substitute teach at the local art school
Ttherefore, she must have practiced her cello on Monday, Tuesday, Thursday, and Friday
Eliza does not practice her cello on the day that she gives cello lessons.