Question 727367
I partly solved but did not finish.  Here is the progress something short of finishing:


{{{3/4-1/8}}} of the tank height is equivalent to 3750 cm^3 of sand.  LET h=tank height.  You already know length and width.


Letting y = amount of height corresponding to 3750 cm^3 of sand, and using 5/8 of h is equivalent to 3750, {{{25*15*y=3750}}} and {{{y=(5/8)h}}}.  Think carefully about these before you continue reading.


That being understood, find that y=10 cm., and then h=16 cm.


Think, how high would be one-eigth of the way up the tank?  How many centimeters?