To answer this item, we let x be the current number of chairs. After adding 50 chairs to the current inventory, the total number of chairs would then be equal to x + 50. The equation that would allow us to determine the value of x is written below.
     x + 50 = (3/2)(x)
Simplifying the equation,
   x + 50 = 3x/2
  x - 3x/2 = -50
   -x/2 = -50
Dividing both sides of the equation by -1/2, the value of x is equal to 100. 
To increase the inventory by 40%, the equation would be,
    y = x(1.4) = 1.4(100) = 140
ANSWER: 140 chairs