When an spherical balloon volume is increasing at the rate of
then the diameter of the balloon is increasing 
How can we find the rate of change of balloon's diameter ?
The volume of a spherical balloon is 
In form of diameter we can write as

Now we will differentiate both sides wrt to
we get

Given in the question 
thus when we substitute the values we get

Learn more about the differentiation here:
brainly.com/question/28046488
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