The difference between the ages of two persons is 30 years. Fifteen years ago, the elder one was twice as old as the younger one. The present age of the younger person is?  Choose the correct option:
A) 30yr
B) 25yr
C) 45yr
D) 40yr
E) 50yr
Let their ages be x years and (x+30) years   Then, (x+30) - 15 = 2(x-15)   x +15 = 2x-30   x = 45   Answer is 45yr
<result>C</result>
The difference between the ages of two persons is 30 years. Fifteen years ago, the elder one was twice as old as the younger one. The present age of the younger person is?