Bat Wings

Two students collected some data on the wingspan of bats, but each lost a measurement. Can you find the missing information?

Kate's Date

When Kate ate a giant date, the average weight of the dates decreased. What was the weight of the date that Kate ate?

Balancing the Books

How many visitors does a tourist attraction need next week in order to break even?

Half a Minute

Age 11 to 14 Challenge Level:

Anna, Ben and Charlie have been using the NRICH timer to see who is best at estimating 30 seconds.

They did this five times each and their times in seconds were recorded in the table below.

Anna	Ben	Charlie
31	36	37
26	19	32
32	39	24
27	36	32
29	20	30

How would you decide who is best at estimating 30 seconds?

If you enjoyed this problem, you might want to have a go at estimating time for yourself - are you better than Anna, Ben and Charlie?

You may also like the problem How Would You Score It?

With thanks to Don Steward, whose ideas formed the basis of this problem.