The system of equations becomes:
s + u = 28 This represent the number of candles sold
16s + 10u = 400 This represents the value of the candles sold
I think 2,057.21 because 18,541.89 divided by 9 is 2,057.21
The volume is 378 ft³. Hope this helps! Good luck.
The concept useful in finding the answer to this item is ratio and proportion, the ratio of the height of your friend with the shadow casted should be proportional to the height of the rock with the length of the shadow it cast. That is,
5.5 ft / 18 ft = x ft/ 209.5 ft
The value of x from the equation above is 64 ft.
It’s already in it’s simplest form!