The average age 20 members of a committee are the same as it was 2 years ago, because an old number has been replaced by a younger number. Find how much younger is the new member than the old number?
Select
A) 18 B) 99 C) 77 D) 40 E) 12
20 * 2= 
<gadget id="calculator">20 * 2</gadget>
<output>40</output>
40 years   Answer: 40
<result>D</result>
The average age 20 members of a committee are the same as it was 2 years ago, because an old number has been replaced by a younger number. Find how much younger is the new member than the old number?