If the base of a rectangular is increased by 10% and the area is unchanged , then the corresponding altitude must to be decreased by?

• A. 10%
• B. 11%
• C. 91/11 %
• D. 111/9 %

Answer: (C)

Let base = b and altitude = h Then, Area = b x h But New base = 110b / 100 = 11b / 10Let New altitude = HThen, Decrese = (h - 10h /11 )= h / 11? Required decrease per cent = (h/11) x (1 / h ) x 100 %= 91/11 %