Question 1190674
<br>
Using formal algebra....<br>
x = John's age (what we are looking for)
2x = twice John's age
2x+4 = 4 more the twice John's age (Patty's age)<br>
Patty's age is 12:<br>
2x+4=12
2x=8
x=4<br>
ANSWER: John is 4 years old<br>
Informally -- to get some good exercise in logical reasoning....<br>
Subtract 4 from Patty's age to get 8 -- to account for the "4 years older"; then
Divide the 8 by 2 to get 4 -- to account for the "twice as old as"<br>
Again of course the answer is 4.<br>