April Mindbenders

The Unlucky Batch

A jeweller’s shop has received new supplies of a popular kind of gold-plated bracelet.  Soon after twelve batches had come in, another had mysteriously appeared.

The manager suspects that a dishonest employee has added a batch of bracelets made with fake gold to the shop’s stock, but doesn’t know which batch this is.  Not wishing to risk getting into trouble for selling these non-genuine articles, he intends to weigh the bracelets in order to find the forgeries.

Fortunately, he knows the weight of a genuine bracelet of this kind.  Unfortunately, he has no idea how much differently one of the imitations will affect the reading on the scales, but is convinced it will be enough to show up.  Fortunately, there are plenty of bracelets in each batch to experiment with.  What is the smallest number of weighings it will take to pick out the bad bracelets?

Answer

Finish the Pattern

Which letter should be in the bottom left corner of this square?

J I W T C G L
L J J C G L J
G L L C G J I
C G G C C I W
Z C C L G C T
N W I J L G N
? W I J L G C

Answer

Now have a go at filling up this incomplete grid of numbers.

4 ? 15
30 6 2
3 10 12

Answer

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