If we use the next formula to determine this:ΔQ=mcΔT
Then we can get to the result. Because of the conservation of energy, the quantity of heat remains the same.
So what we do is:c1∗m1∗(T1−T∗)=c2∗m2∗(T∗−T2)
when plugging in 0.39 for copper and 4.19 we get 29°C for the resulting temperature. I hope this can help you