I think you shouldn't memorize any formula to solve it. But you should know that on the fahrenheit thermometer freezing point is 32 and the boiling point is 212. And in celcius, it is 0 and 100. So we can make the inference that changing 100 units in celcius corresponds to a change of 180 units in fahrenheit. Thus, we should ask that if celcius increase from 0 to 200, what would happen to fahrenheit.
Basic math:
While celcius increase 100, fahrenheit increase 180,
While celcius increase 200, fahreinheit increase 360.
And you shouldn't forget that fahrenheit's freezing point is 32.
32+increase(360)=392
