There are three simplest true fractions, the ratio of their numerators is 3:2:4, and the ratio of their denominators is 5:9:15. Add these three fractions together, and after approximation, it is (28/45). Question: What is the sum of the denominators of the three fractions?
有三个最简真分数，其分子的比为3：2：4，分母的比为5：9：15．将这三个分数相加，再经过约分后为(28/45)．问：三个分数的分母相加是多少．
<gadget id="calculator">5 + 9 + 15</gadget>
<output>29</output>

<gadget id="calculator">7 * 29</gadget>
<output>203</output>

<result>203</result>