How much water at a temperature of 20 degrees Celsius should be added to 100 grams of hot water

How much water at a temperature of 20 degrees Celsius should be added to 100 grams of hot water at a temperature of 50 degrees Celsius. To get water with a temperature of 205 degrees Celsius.

solution
Given t1 = 20 degrees Celsius
m2 = 100 grams – the mass of water at a temperature of t2
t2 = 50C
find m1 – the amount of water in a gram at a temperature of 20 degrees Celsius that must be added to get water with a temperature of t = 205C

Q2 = Q1
c * m2 * (t2 – t) = c * m1 * (t – t1)
m1 = m2 * (t 2 – t) / (t – t1) = 100 grams * 205/5 = 4100 g = 4.1 kg
that is, to get water with a temperature of 205 degrees Celsius, you need to add water weighing 4100 grams with a temperature of 20 degrees Celsius
Answer m1 = 4100 grams