Given mass m1 = 50 grams
Temperature T1 = 20° C
Mass M2 = 50g
Temperature T2 = 20° C
Final Temperature = M1T1 + M2T2 / M1+M2
= 20° C .
Therefore, Final Temperature T= 20° C
*Note: In the question, both masses and temperature are equal of same substance. So, when they keep in contact, no change can be seen sincce their temperatures are same. Hence although they keep in contact they attain thermal equilibrium wth the same Temperature i.e., 20° C