In mathematics, a percentage is a number or ratio expressed as a fraction of 100.
Answer;
Amount of time the two substances are in contact
Area in contact between the two substances
Specific heat of the material that makes up the substances
Explanation;
The change in temperature of a substance is caused by heat energy. The change in temperature will depend on factors such as mass of the substance, the type of material it is made from, the time taken , specific heat of the material that makes the substance, and also the area of contact.
The amount of time the two substances are in contact affect the change in temperature such that if the two bodies are in contact for a longer time then a bigger change in temperature will be observed.
Specific heat capacity also determines the change in temperature that will be observed, such that a substance with a bigger specific heat capacity will record a small change in temperature.
Yah isnt that obvious? Gasses mix everywhere in all proportions.
The efficiency of an ideal Carnot heat engine can be written as:

where

is the temperature of the cold region

is the temperature of the hot region
For the engine in our problem, we have

and

, so the efficiency is