Question

how many combinations of two digit numbers having 8 can be formed from the following numbers 8956​

Answer 1

Answer:

6 is the answer

89. 85. 86. 68. 58. 98

Answer 2

Answer:

7 combinations are possible.

Step-by-step explanation:

Way to solve the problem:

If repetition of digits is allowed-

_ _

First digit can be chosen in 4 ways. (8, 9 , 5 or 6)

Second digit can also be chosen in 4 ways.  (8, 9 , 5 or 6)

Total number of ways in which a two digit combination can be made without any restriction is : 4 x 4 = 16 ways.

Number of ways in which a two digit combination can be made EXCLUDING eight:

First digit can be chosen in 3 ways. ( 9 , 5 or 6)

Second digit can also be chosen in 3 ways. ( 9 , 5 or 6)

Number of ways in which a two digit combination can be made EXCLUDING eight: 3 x 3 = 9 ways.

Therefore,

Number of ways in which a two digit combination can be made having eight is :  Total number of ways in which a two digit combination can be made without any restriction - Number of ways in which a two digit combination can be made EXCLUDING eight

= 16-9

=7

(The combinations are 89,88,85,86,68,58,98)

Solved by complementary counting.