Answer: the number of yards that art bought is 20 3/20 yards
Explanation:
Art bought 7 1/4 yd and 12 9/10 yd for two car projects. We would convert both measurements from mixed fraction to improper fraction before adding.
Converting 7 1/4 yd to improper fraction, it becomes 29/4
Converting 12 9/10 yd to improper fraction, it becomes 129/10 yd
Adding both measurements, it becomes
29/4 + 129/10 = (145 + 258)/20 = 403/20yds
Converting to mixed fraction, it becomes
20 3/20 yards