find a10: 192,196,48

Question

an=a1+(n-1)d
a10=192+(10-1)(?)

i know a1=192, n=10, but what is d?

and find nth term of 1,2,4

a1=1
n=?
r=?

Answer 1

The terms shown cannot all be part of an AP.
So, assuming that 192 and 196 are the first two terms, d=4.

No idea what 48 is doing there.

Now, 1,2,4 is the start of a G.P with
a = 1
r = 2
So, an = 1*2^(n-1)