Answer:
25.5 lbs
Step-by-step explanation:
The total of the first 6 weights is ...
6 × 15 = 90 . . . pounds
The total of the next 14 weights is ...
14 × 30 = 420 . . . pounds
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Then the total of all 6+14 = 20 weights is ...
90 +420 = 510 . . . pounds
and their average is ...
(510 lbs)/20 = 25.5 lbs
The overall average is 25.5 pounds.
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Additional comment
The average is computed from ...
average = (sum of items)/(number of items)
Rearranging this equation gives ...
sum of items = average × (number of items)
The overall average is the sum of all items divided by the number of them.
