Question 1173165
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High water level is  {{{(2/3)*120}}} = 80 cm.


Low  water level is  {{{(1/2)*120}}} = 60 cm.


The change of the water volume is  V = A*(80-60) = 20A cm^3,  where A is the base area, in cm^2.


The volume equation is


    20A = 62600 cm^3


From the equation, the base area  A = {{{62600/20}}} = 3130 cm^2.     <U>ANSWER</U>


To find the new height of the water if extra 1565 cm^3 of water added, add  {{{1565/3130}}}  to 80 cm.  You will get then

    the new level = 80 + {{{1565/3130}}} = 80 + 0.5 = 80.5 cm.     <U>ANSWER</U>
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Solved.