The length of a rectangle is increased by 25%, what percentage should the width be decreased so that the areas of the rectangle remains unchanged ?
সমাধান
সঠিক উত্তর: Option A
Let length = 100x & width =100y
So, area = 100x * 100y
Let p% was decreased
so,
10000xy = (100+25)x*(100y-z)
125xz = 2500xy
=> z = 20y
So % decrease = 20y/100y * 100% = 20%