A, B, C, D and E are 5 consecutive points on a straight line. If BC = 3CD, DE = 7, AB = 5 and AC = 11, what is the length of AE?  Choose the correct choice from the following answers
A) 18
B) 19
C) 20
D) 21
E) 22

Rationale: ac = 11 and ab = 5 , so bc = 6 . bc = 3 cd so cd = 2 . the length of ae is ab + bc + cd + de = 5 + 6 + 2 + 7 = 20 the answer is c .
Answer: C