For a two-digit number, the sum of the ones and tens digits is 15, and the ratio of the tens digit minus 3 to the ones digit is 1:3. What is this two digit number?
一个两位数，个位和十位上的数字之和是15，十位上的数减去3后与个位上的数的比为1：3．这个两位数是多少？
<result>69</result>