Answer: 18
Step-by-step explanation:
Add them all up
18+21+20+14+17=90
Divide by 5 since that is how many numbers there are
90/5=18
The rest of the letters, A, B, C, D, and E all have only 1 line of symmetry. Notice that the A has a vertical line of symmetry, while the B, C, D, and E have a horizontal line of symmetry.
-3x-4<19
19+4=23
3x<23
÷3 ÷3
×= > 23/3 or 7.6^87