MAT3707
ASSIGNMENT 3
SOLUTIONS 2023
Unique number: **********
DUE DATE: 18 AUGUST 2023
DISCRETE
MATHEMATICS:
COMBINATORICS
Page 1 of 18
,SOLUTION:
SOLUTION:
At most n means either
• No 0’s which happens in (64
0
) = 1 way , or
• One 0 which happens in (64
1
) ways , or
• two 0’s which happens in (64
2
) ways , or
• three 0’s which happens in (64
3
) ways , or
• four 0’s which happens in (64
4
) ways , or
• ……
• n 0’s which happens in (64
n
) ways
• These cases are non-overlapping, so we may use the addition principle: the
total is
1+ (64
1
) + (64
2
) + (64
3
) + (64
4
) + …+ (64
n
)
Page 2 of 18
, SOLUTION:
(b) containing at least one 5
SOLUTION:
Page 3 of 18
ASSIGNMENT 3
SOLUTIONS 2023
Unique number: **********
DUE DATE: 18 AUGUST 2023
DISCRETE
MATHEMATICS:
COMBINATORICS
Page 1 of 18
,SOLUTION:
SOLUTION:
At most n means either
• No 0’s which happens in (64
0
) = 1 way , or
• One 0 which happens in (64
1
) ways , or
• two 0’s which happens in (64
2
) ways , or
• three 0’s which happens in (64
3
) ways , or
• four 0’s which happens in (64
4
) ways , or
• ……
• n 0’s which happens in (64
n
) ways
• These cases are non-overlapping, so we may use the addition principle: the
total is
1+ (64
1
) + (64
2
) + (64
3
) + (64
4
) + …+ (64
n
)
Page 2 of 18
, SOLUTION:
(b) containing at least one 5
SOLUTION:
Page 3 of 18