Each month, ERJ sets a weekly brainteaser, with questions of varying degrees of difficulty. Readers supplying the most accurate (and stylish) answers are then considered for the prestigious Brainiac of the Month title.
The water level in a tank is low, but, on refilling, doubles every hour. If it takes 60 hours to fully refill the tank, how long does it take half fill the tank?
Other than minus 12, what can be added to make 8 + 8 = 4 ?