If a: b = 3:4, b:c = 7:9, c:d = 5:7, find a:d?  Pick:
A) 5:12  B) 7:12  C) 3:11  D) 5:11  E) None of these
Explanation:   a/d = (3/4)*(7/9)*(5/7) =&gt; 5/12   5:12nswer is 5:12
<result>A</result>
If a: b = 3:4, b:c = 7:9, c:d = 5:7, find a:d?