### Times

Which times on a digital clock have a line of symmetry? Which look the same upside-down? You might like to try this investigation and find out!

### Clock Hands

This investigation explores using different shapes as the hands of the clock. What things occur as the the hands move.

### Ten Green Bottles

Do you know the rhyme about ten green bottles hanging on a wall? If the first bottle fell at ten past five and the others fell down at 5 minute intervals, what time would the last bottle fall down?

# Timing

##### Stage: 2 Short Challenge Level:

1. Office On Time - As Katherine from the International School, Brunei says the answer depends on the bus driver's watch and whether the bus is on time! Good solutions came from Katherine; from Ben, from a large number of pupils at The Mount School, York; and from Barry, Eaton School, Norwich; James, Hethersett High School, Norwich; Kang Hong, Chinese High School, Singapore; and Steve, Bedlington High School, Northumberland.

Only Tom will catch the bus to work. He will arrive at $7.42$ if he wants to get there $3$ minutes early. John will get there at $8.12$ if he wants to get there $3$ minutes early. This is because, say the exact time was $7.50$ by Tom's watch it would be $8.00$, but he thinks this is $5$ minutes slow, so he would believe the time was $8.05$. This gives him 15 minutes so if he wanted to arrive at the bus stop at $7.57$ by his watch, the actual time would be $7.57 - 15$ minutes $= 7.42$. The same happens for John but in the opposite way therefore he arrives $15$ minutes later, at $8.12$. (Steve, Bedlington High School, Northumberland)

2. Hawaii - Two days before the meeting he is 25 years old and next year he will be 28.

Well done Suzanne, Helen, Charis, Lyndsay, Nisha and Christiane from The Mount School York, and others from The Mount School and especially Christiane who did the time line. Well done also to Kang Hong from The Chinese High School, Singapore, Laura, Ipswich High School; James, Hethersettt High School, Norwich; Alan, Bedlington High School, Northumberland.