Answer
(a) $C(10)=37.3$ dollars
$P(10)=16.8$ dollars
(b) $R(t)=-1.5t^2+17.66t+27.5$
(c) $R(10)=54.1$ dollars
Work Step by Step
$C(t)=-0.9t^2+10.56t+21.7$
$P(t)=-0.6t^2+7.1t+5.8$
$(a)$
Put $t=10$ in the above equations
$C(10)=-0.9(10)^2+10.56(10)+21.7=37.3$
$P(10)=-0.6(10)^2+7.1(10)+5.8=16.8$
(b)
$R(t)=P(t)+C(t)$
$R(t)=-0.6t^2+7.1t+5.8-0.9t^2+10.56t+21.7$
$R(t)=-0.6t^2-0.9t^2+7.1t+10.56t+5.8+21.7$
$R(t)=-1.5t^2+17.66t+27.5$
(c)
$R(10)=-1.5(10)^2+17.66(10)+27.5=54.1$
