A table showing Rate in part per hour, Time in hours, and Part of Room Painted. The first row shows Rocco and has StartFraction 1 Over 7 EndFraction, 3, and StartFraction 3 Over 7 EndFraction t. The second row shows Giulia, and has r, 3, and 3 r. + 3r = 7
+ 3r = 1
= r
= 3r

it takes 7 hours for Rocco to do the job alone.

Step-by-step explanation:

Working together, Rocco and Giulia can paint a room in 3 hours. It would have taken Rocco 7 hours to do the job alone.

the answer is b.

step-by-step explanation:

identity property is where 0+whatever number=whatever number. basically 0+ a number.