Guest Session: 1 Question Remaining.
Create Account
to save progress.
Login
Combinatorics
medium
0:00.0
How many strings of length 4 over
{
a
,
b
,
c
}
\{a, b, c\}
{
a
,
b
,
c
}
contain at least one
a
a
a
?
A
65
B
16
C
51
D
80
Submit Answer