Answer:
9kg
Explanation:
If a 10kg object exerts a weight of 80N, it means that the gravitational acceleration is 8N/kg. This means that the weight of an object will be 8x its mass. So, if we want to find an object's mass from its weight, we simply need to divide it by 8. 72/8=9. The other object has a mass of 9kg.
Hope this helped!