What efficiency would an ideal heat engine operating according to the Carnot cycle have if its heater were heated

What efficiency would an ideal heat engine operating according to the Carnot cycle have if its heater were heated to a temperature T1 = 2700 K, which can be obtained by burning gasoline, and the ambient air at a temperature of T2 = 300 K would serve as a refrigerator?

First, we write down the equation for finding the efficiency for an ideal heat engine:
η = ((T (n) – T (x)) / T (n)) * 100%
Now let’s find the efficiency:
η = ((2700 – 300) / 2700) * 100% = 88.8%