Answer:
a = 1/2, b = 32.
Step-by-step explanation:
Second = a1r and fifth = a1r^4 where r = common ratio and a1 is the first mean after a.
So 1ar^4 / a1r = r^3 = 16/2
r^3 = 8
r = 2.
So a1 = 1.
The 5 means are 1, 2, 4, 8, 16
S0 a = 1/2 = 1/2 and b = 2*16 = 32.