Answer:
Only 4 hours
Explanation:
8 children made a sandcastle in 5 hours. 8:5 ratio
10 children made a sandcastle in ? 10:? ratio is it?
Remember, It's inversely proportional, which means, more people, less time to take it to make the sand castle. So we would do, 8*? = 10 that would be 1.25. 8*1.25=10. then, do 5/1.25, cause it's "inversely proportional. I'm not sure if this is right, but I think it is 4 hours.