Reasoning
In 36 hours, Alex could empty 2 lots of bookshelves, Billie could also empty 2 lots of bookshelves, and Drew could refill 1 lot of bookshelves.
So, 2 + 2 – 1 = 3 lots of bookshelves in 36 hours. Which is 12 hours for one lot of bookshelves.
Alternative Reasoning
Alex and Billie can each empty 1/18 of the bookshelves in 1 hour, but Drew will refill 1/36 of the bookshelves in one hour.
So in one hour we have 1/18 + 1/18 – 1/36 = 1/12.
So it would take 12 hours to empty the bookshelves.
At a recent painting competition, the results were mislaid. Luckily, I remembered the following:
Emery's rendition of the Constable painting was not in last place. The person who painted the Monet was very successful and took first place. Glen only just managed to avoid last place and came third. Alex beat the person who painted the Taylor, and the person who painted the Van Gogh beat Drew.
Can you determine who painted what, and who won?
Answer # Name Artist
1 Alex Monet
2 Emery Constable
3 Glen Van Gogh
4 Drew Taylor Reasoning
The four entrants were: Alex, Drew, Emery, Glen.
The four artists were: Constable, Monet, Taylor, Van Gogh.
By (2), the Monet came first.
1 Monet
2
3
4
By (3), Glen came third.
1 Monet
2
3 Glen
4
By (1), the Constable can't have been last, so must have been second (as Emery painted it, and not Glen).
1 Monet
2 Constable
3 Glen
4
The Taylor was either third or fourth, either way, by (4) Alex must have won.
1 Alex Monet
2 Constable
3 Glen
4
By (4), the Van Gogh came third, leaving Drew in last place.
1 Alex Monet
2 Constable
3 Glen Van Gogh
4 Drew
Leaving Emery in second place, and the Taylor in last place.
1 Alex Monet
2 Emery Constable
3 Glen Van Gogh
4 Drew Taylor
