Question

breadth and height of a cuboidal are reservior there is 7 m 6 m and 15 m respectively 8400 litre of water is pumped out from the reservior find the fall in the water level in the reservior

Answer 1

$\bf\huge\textbf{\underline{\underline{According\:to\:the\:Question}}}$  

$\bf\huge\bf\huge{\boxed{\bigstar{{Height\:of\:Water\:tank\:=\:6m}}}}$        

Change litres to metre

$\bf\huge\bf\huge{\boxed{\bigstar{{8400L = 8.4m^3}}}}$        

Height of the water pumped out:

Volume = Length × Breadth × h

8.4 = 7 × 6 × h

8.4 = 42 × h

height = $\sf{\implies\dfrac{8.4}{42}}$    

$\bf\huge\bf\huge{\boxed{\bigstar{{h = 0.2m}}}}$            

$\bf\huge\bf\huge{\boxed{\bigstar{{Water\:Level\:fell\:=\:0.2}}}}$