The manufacturing process for making a 55 cm X 70 cm antiviral silver coated plastic sheet used to make a face shield involves heating the material at 400°C followed by a special treatment at 360°C...

question in image. only need help with 2nd question

Extracted text: The manufacturing process for making a 55 cm X 70 cm antiviral silver coated plastic sheet used to make a face shield involves heating the material at 400°C followed by a special treatment at 360°C for 20 mins. When a uniform temperature of 360°C is reached within the material, the silver coated sheet is immersed into a solution at 30°C. The thickness of this silver coated sheet is 9 mm. What is the time at which the temperature of the sheet becomes 125 °C ? Properties of the sheet: Density: 8500kg/m3; Cp= 0.37 kJ/kgK; thermal conductivity, K= 380 W/mK; convective heat transfer coefficient, h=110 W/w2K. .What is the rate of cooling after 2 mins?