10 Trees in 5 rows

How can you plant 10 trees such that they are planted in 5 rows of 4 trees each?

Three students

Alex is an art-student who sends an email to Bert. Charles is not an art-student. Bert sends an email to Charles.

Now the simple question is: Does an art student send an email to someone who is not an art student?

Yes or No? Or can’t decide because of lack of information?.

This puzzle comes from a presentation by Paul Fenwick, which you can find here

If you solved it, we have the solution so you can check yours.

Pattern code snakes

1) Snakes
What is the code that goes into the question mark?

You can check your solution

Sums with swapped doubles

In this type of puzzle: swap two pairs of digits to make the addition correct. For example, in the illustration above the 7 and the adjacent 0 might have been swapped, or the 3 with one of the 8’s. Your task of course is to restore the original correct sum by finding the two swaps.

1) nr 1^*

1486
3172
—-+
7313

2) nr 2^*
3155
4349
—-+
7317

3) nr 3^*
2748
6146
—-+
6134

4) nr 4^*
9559
1326
—-+
5418

5) nr 5^*
See the illustration at the top of this post.

Nr 3 comes from Issue no 41, 1975, of the famous British magazin Games and Puzzles. I suppose an anonymous editor came up with this puzzle type.
If you have other information about the origin of this puzzle type, I’d love to hear it.

You can find the solutions at 137, 147, 157, 167 and 177

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