If the edge of a cube increased at the rate of 60cm per second at what rate the volume is increasing when the edge is 90cm

hi,

ur queswtion is a simple use of derivatives

rate of increase of side say 'a', is da/dt = 60

since volume of a cube  , v = a^3

so dv/dt = 3*a² * da/dt

here dv/dt = rate of increase of volume

so dv/dt = 3* 90*90* 60

            = 1458000 cubic centimeter / sec