A puzzle from my nephews in Kolkata
Reeling under the lack of power, water supply and all that the devastating cyclone Amphan left behind, apparently my nephews hunkered down and started doing puzzles. They could not wait for power to come back – so that they could recharge their phones and send me this problem thru Whatsapp.
Good problem. About 2 years back, I had posted a similar version of the problem.