Question 842477
Same as asking find t for the derivative of R equal to zero.
(*See note below)


{{{dR/(dt)=-12t^2+38}}}
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Find solution for t, for the one such that {{{t>0}}}.
{{{-12t^2+38=0}}}
{{{12t^2=38}}}
{{{6t^2=19}}}
{{{highlight(t=sqrt(19/6))}}} years
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This time quantity is 1.78 years, or 1 year 41 weeks.




* assumed your equation was to be {{{R=-4t^highlight(3)+38t}}}