A child withdraws from his piggy bank 10% of the original sum in the bank. If he must add 90￠ to bring the amount in the bank back up to the original sum, what was the original sum in the bank ？（）

The width of a rectangle is 6 cm less than the length. ...

单项选择题The width of a rectangle is 6 cm less than the length. If the perimeter of the rectangle is 48 cm, what is the length of the rectangle in centimeters ？（）