



 
Hi Tracy, The volume of the Tootsie Roll Pop and its radius are not constant, they are both functions of time t. Let V(t) be the volume in cubic centimeters and r(t) be the radius in centimeters at time t minutes. The relationship between them is
1 milliliter is 1 cubic centimeter so you know that
Differentiate V(t) implicitly with respect to t to find an equation for V'(t) in terms of r(t) and r'(t). Substitute r(t) and V(t) when r(t) = 20/2 = 10 mm. Watch out for the units change. You should probably express the radius in cm rather than mm. Harley  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 