Answer: 15 degrees.
Step-by-step explanation:
A bisector divides an angle in half. So, we know the total angle of ABC is 20 degrees, as show in blue. We draw the bisector BD in the middle, meaning each side is 10 degrees, show in green. This means angle ABD is 10 degrees and angle CBD is is 10 degrees. We bisect angle CBD with BE, shown in red. This means that we have two 5 degree angles on either side, angle CBE and angle EBD. Lastly, we need to find angle ABE, highlighted in orange. We add the components, which are angle DBA, measuring 10 degrees, and angle EBD, measuring 5 degrees. When added together, this equals 15 degrees, which is our final answer for angle ABE.