The formula for Newton Law of cooling is

T(t) = T _s + (T _o – T _s ) e ^-kt

Here you should note that,

t = time,

T(t) = temperature of the given body at time t,

T _s = surrounding temperature,

T _o = initial temperature of the body,

k = constant.

You must know that the rate of heat loss from a body is directly proportional to the difference in temperature between the body and its surroundings, according to Newton's law of cooling.

It is one of the most useful and well-known formula of thermodynamics and you will get to read about it higher studies too.

Infact, this is a whole topic in itself to study.

I hope this information helps you.

All the very best!!