answer：11
Solution：
let n equals the difference between Zoe’s and Chloe’s ages. The condition works when n has 9 factors. By inspection, 36 has 9 factors. Thus, Joey is 38 and will be 74 when Zoe is 37, so the answer is 7+4=11 .
解答：
假设n是田田和妈妈的年龄差，从题意得知n有9个因子。据观察得知36有9个因子。所以，爸爸今年38，当田田37岁的时候爸爸74岁。4+7=11.