Question 412877
Since Susan can paint a room in 6 hours, she can paint 1/6 of a room in an hour.
Since Tom can paint a room in 5 hours, he can paint 1/5 of a room in an hour.

After x hours, they together can paint

1/6 x + 1/5 x rooms

1/6 x + 1/5 x = 1

(1/6 + 1/5) x = 1

11/30 x = 1

x = 30/11 hours