Find the difference between the two times
= 4 2/5 - 2 1/4
convert each mixed number to an improper fraction
= 22/5 - 9/4
change to common denominator (20)
= 88/20 - 45/20
subtract numerators only
= 43/20
change back to mixed number
= 2 3/20
ANSWER: It took 2 3/20 hours longer to clean the bathroom.
Hope this helps! :)