A cup of hot chocolate is initially 170F and is left in a room with ambient temperature of 70F. suppose tht at time t=0, it is cooling at a rate of 20 degrees per minute

Assume that newtons law of cooling applies: the rate of cooling is portortional to the difference between the current termperate and the ambient temperature

how long does it take the hot chocolate to cool to a temperate of 110 F?