How Long to Boil a Larger Kettle of Water?

[pixel01]

My friend asks me this question, I have not worked it out.
I hope it is suitable to maths box .

The time to boil a small kettle of water using a electric coil is A minutes.
Q: How many minutes needed to boil a big kettle (two times the mass of water compared to the small kettle), if using the same coil. Consider no heat is transmitted away to the ambient.

 

[marcusl]

It is 2A

 

[Crosson]

Is it the same metal kettle the entire time?

If so, then the answer is 2A.

Also, this would be a better fit in the general physics forum than in general math.