another one XD (1 Viewer)

[me dumb]

question 4c)i)
View attachment 18883
i got a different answer of 0.143239448cm/sec
i got part ii) correct, are the answers wrong or me XD

 

[lychnobity]

given radius=10 & height = 20cm

r/h = 1/2, h=2r

Volume of Cone = 1/3 πr²h
V = 1/3 πr²(2r)
= 2/3 πr³

dV/dr = 2πr²

dr/dt = dV/dt . dr/dV
= 30 x 1/2πr²
= 15/πr²

r=5, dr/dt = 15/π(5²) = 3/5π