when linda and martin work together painting one room, they can complete the work in 5 hours. when linda works alone it takes her 7 hours to paint the same room. how long would it take marvin to paint the room alone?

Answer 1

linda --- 1 room/7 hours
marvin ---- 1 room/x hours

5 hours (1/7 + 1/x) = 1

1/7 + 1/x = 1/5

multiply all terms by 35 x
5 x + 35 = 7x
2 x = 35
x = 17.5 hours