Question 1208899
<font color=black size=3>
Answer:  <font color=red>$3000</font>


Explanation


a = Andrew's amount before the $300 is added later
3a-600 = Beatrice's amount


After Andrew gets an extra $300 (which I'm assuming is not from Beatrice), then the "a" becomes a+300.


Then,
Andrew's amount = (1/2)*(Beatrice's amount)
Beatrice's amount = 2*(Andrew's amount)
3a-600 = 2*(a+300)
3a-600 = 2a+600
3a-2a = 600+600
a = 1200
Andrew starts off with $1200.


Beatrice has 3a-600 = 3*1200-600 = 3600-600 = <font color=red>$3000</font>


If Andrew gets that extra $300, then he'll have $1200 + $300 = $1500 which is half of the $3000 Beatrice has. This helps confirm the answer is correct.
</font>