题目：一个数的\frac{2}{9}是\frac{1}{5}，这个数是多少?正确算式是( ) 
选项：
bullet: A
text: \frac{2}{9}×\frac{1}{5}
bullet: B
text: \frac{2}{9}÷\frac{1}{5}
bullet: C
text: \frac{1}{5}×\frac{2}{9}
bullet: D
text: \frac{1}{5}÷\frac{2}{9}
答案：D
解析：\frac{1}{5}÷\frac{2}{9}=\frac{9}{10}; 故选D.