# Straight line sum - math puzzle

Correct the equation above by inserting one straight line.

# Thousand monkeys - math puzzle

A very big building in which thousand monkeys are living is lighted by
thousand lamps. Every lamp is connected to a unique on/off switch, which are numbered from 1 to 1000. At some moment, all lamps are switched off. But because it is becoming darker, the monkeys would like to switch on the lights. They will do this in the following way.

Monkey 1 presses all switches that are a multiple of 1.

Monkey 2 presses all switches that are a multiple of 2.

Monkey 3 presses all switches that are a multiple of 3.

Monkey 4 presses all switches that are a multiple of 4.

Etc., etc.

How many lamps are switched on after monkey 1000 pressed his switches? And which lamps are switched on?

Monkey 1 presses all switches that are a multiple of 1.

Monkey 2 presses all switches that are a multiple of 2.

Monkey 3 presses all switches that are a multiple of 3.

Monkey 4 presses all switches that are a multiple of 4.

Etc., etc.

How many lamps are switched on after monkey 1000 pressed his switches? And which lamps are switched on?

# Let's go for a hike - math puzzle

A hiker walked for two days. On the second day the hiker walked 2 hours longer and at an average speed 1 mph faster than he walked on the first day. If during the two days he walked a total of 64 miles and spent a total of 18 hours walking, what was his average speed on the first day?