Answer
$2.495$
Work Step by Step
We have $C=0.45x^2-1.65x+50.75$
Plug in $x=10$,
$\implies 0.45(10)^2-1.65(10)+50.75=79.25$
Plug in $x=20$,
$\implies 0.45(20)^2-1.65(20)+50.75=197.75$
The oxygen consumption is increased by approximately $\frac{197.75}{79.25}\approx 2.495$
