Answer :
The weight of the last child is 36 lbs.
How to calculate the mean?
The average weight of the three children is 60 lbs. The total weight will be:
= 60 × 3
= 180 lbs.
When another child is added, the weight is 54lb. The total weight will be:
= 54 × 4
= 216 lbs
The weight of the last child will be:
= 216 - 180
= 36 lbs.
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