Question

1) Let A = {1, 2, · · · , 10} and B = {1,2,3, a, b, c, d} then   |A   ∩B|=

2) How many 8 digit telephone numbers can be made from {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} such that the first digit is not 0? (Repetition of a digit is allowed.)

3) Let A = {1, 2, · · · , 10} and B = {1,2,3, a, b, c, d} then   |A   − B|=

4) Let A = {1, 2, · · · , 10} and B = {1,2,3, a, b, c, d} then   |A   xB|=

5) How many 4-digit secret codes can be framed for the credit card of a bank using the digits {1,2,3,4,5,6,7,8,9}? (repetition of a digit is allowed.)

Answer 1