Carol is four times Alice’s age but only twice as old as Betty. Alice is thirty-six years younger than Carol. How old is Betty?	Choose one:
A) 36  B) 39  C) 42  D) 48  E) 24
Beyond the obvious Algebra approach to this question, it can also be solved by TESTing THE ANSWERS.   We're told 3 facts about the relative ages of 3 people:   1) Carol's age is 4 times Alice's age   2) Carol's age is 2 times Betty's age   3) Carol is 36 years older than Alice   We're asked for BETTY'S age.   Since Carol is TWICE Betty's age, Betty is clearly younger than Carol, so we'll TEST smaller answer first.   IF....   Betty = 24   Then Carol = 2(24) = 48   Then Alice = 48 - 36= 
<gadget id="calculator">48 - 36</gadget>
<output>12</output>
12 AND   48/4= 
<gadget id="calculator">  48/4</gadget>
<output>12</output>
12   All of these values mesh perfectly with the facts and with one another, so Betty MUST be 24   24
<result>E</result>
Carol is four times Alice’s age but only twice as old as Betty. Alice is thirty-six years younger than Carol. How old is Betty?