The complete pattern is: 512, 256, 128, 64, 32, 16, 8, ( and extended ) 4, 2, 1!
I do this pattern in my head literally all the time!
1. There are 6 green bulbs because
13+5=18*1/3=6 green bulbs
2. The probability of getting a red bulb is 15/8
Hope it helps you!!!!
The answer would be c but why u have d