This is a geometric sequence with common ratio (r) = 2.
an = ar^(n - 1)
a4 = a(2)^(4 - 1) = a(2)^3 = 8a
8a = 80
a = 80/8 = 10
7th term (a7) = 10(2)^(7 - 1) = 10(2^6) = 10(64) = 640
Z=kx, 30=8k, so k=30/8=15/4 and z=15x/4, so when x=4, z=15.
Probability of first red = 1/5
and Probabiliiy of the green =1/5 the red again is 1/5.
Required probability is (1/5)^3 = 1/125
its D
Answer:
The first one
Step-by-step explanation:
You can see the pattern
