The answer to your question is that you are not correct you have to read between the lines
P=4*a, where P - perimeter, a - length of one side of the square.
if a=x+3 and P=48, then 4(x+3)=48;
x=9.
Answer: 9 units.
The available balance online may not reflect all debit transactions or all checks that were written. Some recent debit transactions and check written may not have been posted to his account yet. The available balance would need to subtract any outstanding debit transactions and any written checks that have not cleared his account. This would yield the correct available balance.
The correct answer is line q