Bucket of water
Lisa's bucket weighs 21 kg when full of water. After she pours out half the water it weighs 12 kg. What is the weight of the empty bucket?
Age
11 to 14
Challenge level
Problem
Lisa's bucket weighs 21 kg when full of water.
After she pours out half the water from the bucket it weighs 12 kg.
What is the weight of the empty bucket?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Student Solutions
Answer: $3\text{kg}$
The weight of the water poured out is $21-12=9\text{kg}$.
Thus the weight of the bucket is $12-9=3\text{kg}$.