Aptitude Day 75

Ratio and Proportion:

1. If x:y = 4:1, then (x²-y²) : (x²+y²) is

Solution:

               x²/y² = 16/1

              (x²-y²) / (x²+y²) = (16-1) / (16+1)

                                          = 15/17.

              (x²-y²) : (x²+y²) = 15:17.

2. If (x²-3y²) : (x²-y²) = 1:3, then x:y is:

Solution:

             (x²-3y²) / (x²-y²)  = 1/3

             3x²-9y² = x²-y²

             2x²=8y²

             x²/y² = 4

             x/y = 2.

         

            The ratio is 2:1.