Aptitude Day 78

Ratio and Proportion:

1. If (a+ b): (b+ c): (c+ a) = 8:9:10 and a+ b+ c = 36. Find the value of a.

Solution:

                Let  a+b = 8x, b+c = 9x, and c+a = 10x.

               Adding these 3 equations, we get

               2(a+b+c) = 27x

               2(36) = 27x

               x = 8/3.

               b+c  = 9x = 24.

              (a+b+c)-(b+c) = 36 – 24

              a = 12.

2. The salaries of A, B and C are in the ratio 3:5:7. If the increments of 10%,20% and 30% are allowed respectively in their salaries, then what will be the new ratio of their salaries?

Solution:

                 Let the new ratio be a: b: c.

                 a = (110/100)3x = 33x/10.

                 b = (120/100)5x = 6x.

                 c = (130/100)7x = 91x/10.

                 [Note: 100+10 = 110, 100+20 = 120 and 100+30 = 130 are due to the increments by 10%, 20% and 30% respectively]

                 a: b: c is 33x/10 : 6x : 91x/10

                             = 33 : 60 : 91.