Answer:
Step-by-step explanation:
Amount of heat required can be found from the following relation 
Q = mcΔT
m is mass of the body , c is specific heat and ΔTis rise in temperature . 
Here m = 300 kg 
c = 3350 J /kg k 
ΔT = 30 - 25 
= 5 °C
Putting the values in the expression above 
Q = 300 x 3350 x 5 
= 5025000 J 
Rate at which energy is absorbed = 1200 J /s 
Time required
= 5025000 / 1200
= 4187.5 S 
= 69.8 minute
= 1 hour 9.8 mimutes.