The angle of elevation of the top of a pillar from the foot and the top of a building 20 m high, are 60° and 30° respectively. The height of the pillar is
____ jointly launched International Solar Alliance (ISA) at Conference of Parties (CoP21) Climate Conference held in Paris, France on 1st December 2015.
Two identical resistors, each of 10 ohm, are connected in parallel. This combination, in turn, is connected to a third resistor of 10 ohm. The equivalent resistance of the combination is ___.