Answer:
- The final temperature in the container with Gold is  27.49 ⁰C
- The final temperature in the container with Iron is  33.01  ⁰C
Therefore, the highest final temperature is obtained in the container with Iron.
Explanation:
Q = mcΔT
Where;
Q is the quantity of heat gained or lost
m is the mass of the metals or water
c is the specific heat capacity
ΔT is the change in temperature, T₂ - T₁
T₂  is the final temperature and T₁ is the initial temperature
Heat lost by metals at 100°C is equal to heat gained by water at 25°C


Specific heat capacity of water = 4.18 J/g°C
Specific heat capacity of gold = 0.129 J/g°C
Specific heat capacity of iron  = 0.45 J/g°C
⇒For Gold
-20*0.129*(T₂ - 100) = 18*4.18 (T₂ - 25)
-2.58T₂ +258 = 75.24T₂  - 1881
77.82T₂  = 2139
T₂  = 2139/77.82
T₂  = 27.49 ⁰C
⇒For Iron
-20*0.450*(T₂ - 100) = 18*4.18 (T₂  - 25)
-9T₂  +900 = 75.24T₂ - 1881
84.24T₂ = 2781
T₂  = 2781/84.24
T₂ = 33.01  ⁰C
Therefore, the highest final temperature is obtained in the container with Iron.