Delhi Police Constable Exam Model Paper 6

Given, ten years ago, the elder brother was twice the age of the younger one.
Let, the age of younger brother ten years ago = x
then, the age of elder brother ten years ago = 2x
Present ages:
Elder brother = 2x + 10
Younger brother = x + 10
Since, the sum of the present ages of 2 brothers is 50.Thus, x + 10 + 2x + 10 = 50
x = 10
Present age of the elder brother = 2 × 10 + 10 = 30
Hence, 30 years is the correct answer.