Question 1151259
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The original formulation in the post is  DEFECTIVE,  INACCURATE  and potentially  DANGEROUS.


The correct,  accurate and safe formulation is  THIS :



<pre>
      Liza is one year older than her sister. In four years Liza will be three times {{{highlight(cross(older_than))}}} <U>as old as</U> she is now. 
      How old is Liza's sister now?
</pre>


<U>Solution</U>


<pre>
Let x be the Lisa's age now.


Then from the condition


    x + 4 = 3x.     (In four years Liza will be three times as old as she is now).


From the equation,

    4 = 3x - x

    4 = 2x

    x = 4/2 = 2.


So, Lisa is 2 years old now.


<U>ANSWER</U>.  Lisa' sister is 2-1 = 1 year old now.
</pre>

Solved.



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Here I want to explain you, &nbsp;why the original formulation in the post is &nbsp;DEFECTIVE, &nbsp;INACCURATE &nbsp;and potentially &nbsp;DANGEROUS.


In English, &nbsp;in distinction from many other languages, &nbsp;the statement


<pre>
    In four years Liza will be three times older than she is now.
</pre>

means  "In four years Liza will be FOUR times as old as she is now."


In English, &nbsp;it is the only possible interpretation --- and there is &nbsp;NO &nbsp;any other interpretation.


But it is, &nbsp;certainly and definitely, &nbsp;not that meaning the author of the problem was going to implement.


Probably, &nbsp;the author of the problem is/was not familiar with this norm/form of English --- so, &nbsp;learn it from my post.



The second message from me is that the &nbsp;"solution" &nbsp;and the setup in the post by &nbsp;@josgarithmetic is &nbsp;WRONG.


So, &nbsp;you better &nbsp;IGNORE&nbsp; his post for your safety.