For a two-digit number, the number on the tens digit is twice that of the ones digit. If the ones digit and the tens digit of this two-digit number are reversed, the new two digits obtained are the same as the original two digits. The sum is 66． Find the original two-digit number.
一个两位数，十位数上的数字是个位数上的两倍，如果把这个两位数的个位上数字和十位上对调，所得到的新的两位数与原来的两位数的和是66．求原来的两位数．
<result>42</result>