题目内容：

已知C,D为线段AB上两点,AC:CB=5:7,AD:DB=5:11,若CD=10cm,求AB的长.

优质解答

AC:CB=5:7
则 AC=5/12AB
AD:DB=5:11
则 AD=5/16AB
CD=AC-AD
=(5/12-5/16)AB
=5/48AB
AB=CD*48/5=96cm