How to calculate time if you have heating rate and temperature

Try solving this problem:

How to calculate A time and B time? You need to use this equation: 

 

..........(eq. 1)

Solving A:

Heating rate  = 5 °C/min

Time            = A

Temperature = (T₂-T₁) = (650-30) °C = 620 °C

Based on equation 1: 

t = 124 min = 2 hours 4 min = 2.067 hours. 

To solve B is same as calculate A. 

Try calculate B. The answer for B time is; t = 1.033 hours.

Thank you~