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### Number and algebra

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# Bat Wings

## You may also like

### Kate's Date

### Balancing the Books

### Grandpa's Rock Cakes

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Age 11 to 14

ShortChallenge Level

- Problem
- Solutions

Here is a table of information about the wingspan of bats. Unfortunately, two entries are missing from the table.

Student | Data set (wingspans in cm) | Mean (cm) | |||||
---|---|---|---|---|---|---|---|

A | 13 | - | 16 | 12 | 10 | 15 | 13 |

B | 13 | 16 | - | 13 |

Student A collected 6 measurements and worked out that their mean was 13cm.

Student B collected 4 measurements.

The overall mean of the combined data was 13.4cm.

**Can you work out what the two missing values are?**

You can find more short problems, arranged by curriculum topic, in our short problems collection.

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

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

Grandpa made a super-heavy rock cake. Five people have guessed the weight of the cake. Can you work out the weight of his cake?