map

Routes from the towns

A, B, and C are three towns, each connected by a network of roads. There are 82 ways to get from A to B, including those routes that pass through C. There are 62 ways to get from B to C, including those routes that pass through A.

Saccorhytus coronarius

Scientists find ‘oldest human ancestor’

Researchers have discovered the earliest known ancestor of humans – along with a vast range of other species. They say that fossilised traces of the 540-million-year-old creature are “exquisitely well preserved”. The microscopic sea animal is the earliest known step on the evolutionary path that led to fish and – eventually – to humans.

penny coin

Two coins in a box

A sealed box contains two coins. One is a double-headed coin, and the other is an ordinary coin (heads on one side, and tails on the other). You take one of the coins out of the box and look at one of the sides.