Question 1169427
.
<pre>

If two years ago, the younger sister is seven years old,

    hence, the younger sister is 9 years old now.



Thrice 9 years is 27 years, and 4 less than 27 years is 23 years.


<U>ANSWER</U>.  Liza is 23 years old now.
</pre>

Solved.