The metabolic rate of an ectothermic organism increases with increasing temperature within a certain range. Experimental data for the oxygen consumption C (in microliters per gram per hour) of a beetle at certain temperatures can be approximated by the model

C = 0.45x2 − 1.65x + 50.75, 10 ≤ x ≤ 25

where x is the air temperature in degrees Celsius.

(a) The oxygen consumption is 150 microliters per gram per hour. What is the air temperature?

(b) When the air temperature increases from 10°C to 20°C, the oxygen consumption increases by approximately what factor?