I like the 'question mark' at the end:
26 letters (English), 10 digits (0,1,...9)
26*26*10*10*10 = 676000
Now, this was for LLDDD (Letter Letter Digit Digit Digit)
It seems this is the order they want. Other wise, one should multiply by all the combinations in the order: LDLDD, DLLDD, etc ... (10 combinations), but again it seems they want this LLDDD
So 676000
Is there a picture of the question?
A
this is a geometric sequence since there exists a common ratio r between the terms
r =
=
=
= 3
B
to obtain the next term in the sequence multiply the previous term by 3
= 3
← recursive rule
C
the n th term of a geometric sequence is
=

where
is the first term in the sequence
= 7 ×
← explicit rule
Answer:
c
Step-by-step explanation: