<PRE><B>Question 1036526</B>
Volume of the cube: 15^3 = 3375 cm^3
3/4 full: 3375*3/4 = 2531.25 cm^3
Volume of the marble:
4/3(4^3*Pi)=268.08 cm^3
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3/4 cube + marble:
2531.25+268.08 = 2799.33 cm^3
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At 3/4 full, the water is up to the 11.25cm mark. When we drop the marble in the cube it goes up to 2799.33/3375 = 0.8292 
0.8294*15 = 12.44 cm is the new mark</PRE>