The difference between the ages of two persons is 11 years. Ten years ago, the elder one was twice as old as the younger one. The present age of the elder person is	Pick one: A) 18 B) 19 C) 20 D) 17 E) 16
Let their ages of x years and (x + 11) years respectively.   Then, (x + 11) - 10 = 2(x - 10)   ⇔ x +1 = 2x - 20   ⇔ 3x = 21.   ∴ Present age of the elder person = (7 + 11)= 
<gadget id="calculator">(7 + 11)</gadget>
<output>18</output>
18years.   18nswer :18 years
<result>A</result>
The difference between the ages of two persons is 11 years. Ten years ago, the elder one was twice as old as the younger one. The present age of the elder person is