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So the missing measurement can be found by subtracting the five known wingspans from the total: 78 - (13+16+12+10+15) = 12 cm.
Next, we can find student B's mean using the total mean:
There are 10 bats altogether, and the average wingspan is 13.4 cm, so the total wingspan is 10\times13.4 = 134 cm.
We already know that student A's bats' had a total wingspan of 78 cm. So student B's bats' total wingspan must be 134 - 78 = 56 cm.
So B's missing measurement can be found by subtracting the three known wingspans from the total: 56 - (13+16+13) = 14 cm.
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?