Aptitude Day 48

Answer of Day 47:  9

Problems on Numbers

1. Two numbers are such that the ratio between them is 2:9. If each is increased by 3, the ratio becomes 3/10. The smaller number is:

Solution:
                (2x+3)/(9x+3) = 3/10
                 10(2x+3) = 3(9x+3)
                    20x+30 = 27x+9
                            7x = 21
                              x = 3.
               The smaller number is 2(3)= 6.

2.  The sum of three numbers is 27. If the first number is thrice of third number and the second number is half of the third number. What's the third number?

Solution:
               Let the third number be x.
               3x+1/2(x)+x = 27
                     6x+x+2x = 27*2
                                 9x=27*2
                                   x= 6.
             The third number is 6.