If it jake 2/3 hours to paint 2/5 of his room, how long would it take to paint his sister's room?

Assuming his room and his sisters room are the same size
(2/3)/2=1/3 hour to paint 1/5 of his room
(1/3) x 5= 5/3 hours to pain the entire room

20 percentage, you can also do it on a calculator.