Aptitude Day 39

Problems on Numbers

1. A number is doubled and 5 is added. If the resultant is tripled, it becomes 33. What's the number?

Solution:
                 Let the number be x.
                 3(2x+5) = 33
                    6x+15 = 33
                           6x=18
                             x=3.
                 The number is 3.

2. When 18 is subtracted from a number, it reduces to its three-fifth. What's the sum of the digits of that number?

Solution:
               Let the number be x.
               x-18=3/5(x)
               x-3/5(x) = 18
               5x-3x = 90
                     2x = 90
                       x = 45.
              The sum of the digits of the number is 4+5 = 9. 
                 
Problem to solve

Three-fifth of a number is 25 more than the half of the number. What's the number?