Question

A sign writer was observed painting a wall at a uniform rate. By 3pm he was 1/3 of the way up. By 4pm he was 5/6 of the way up. At what time did he reach the top?

Answer 1

4:10 pm

Answer 2

no

Answer 3

4:20

Answer 4

how

Answer 5

from 3pm to 4pm he went from 1/3 to 5/6 which is equivalent to
2/6 to 5/6. That's an increase of 3/6 over 1 hour.

So 1hr = 3/6
60min = 3/6
divide both sides by 3 getting
20min = 1/6
Since he only needs 1/6 more to finish, just add 20min to his last time of 4pm to get 4:20