2 because 8 divided by 4 is 2.
Answer:
0.0078125
Step-by-step explanation:
If the probability of flipping a fair coin (mentally) correctly for 1 row is 0.5, then the probability of flipping it correctly for 2 rows is
0.5 * 0.5 = 0.25
for 3 rows: 0.5*0.5*0.5 = 0.125
...
For 7 rows:

The train is traveling at 165 mph
495/3=165
825/5=165
1155/7=165
1485/9=165
A^2-5a = 6
a^2-5a-6 = 0
Discriminant = (-5)^2-4(1)(-6) = 49
Discriminant is positive so there are two solutions