Calculus
posted by Mehak .
A water trough on a farm has an isosceles triangle croos section which is 60 cm across the top and 20m deep.the trough is 3m long . If itbis empty and then filled at a rate of 0.5 m3/min , how fast does the water level rise when the deepest point is 9cm ?

This problem is similar to one of your previous questions:
See:
http://www.jiskha.com/display.cgi?id=1299996707