Since we know AC = 26 and E is half way between A and C then AE would be 13.
EC is the same as AE since E is the mid point and thus EC must also be 13.
BC we cannot tell from the information. From what we know if could be anywhere from 2 to 50. If both line AB and AC on top of eachother than you take 26 - 24 = 2 or if they are opposite then the distance would be 26+24 =50.
BD = 12 since D is the midpoint of AB and we know that AD = 12
AB = 24 since it is twice the length of AD.
Hope this makes sense. If you want me to send you a drawing of the lines let me know.