Let the side of the equilateral triangle be x cm, then the area of the equilateral triangle is
So as per the question rate of side increasing at instant of time t is dx/dt = 2 cm/sec
Now differentiating area with respect to time t, we get
Now substituting the given value of dx/dt, we get
Hence, the rate at which the area increases, when side is 10 cm is 10√3 cm2/s.
So the correct option is option C.