Question

At the beginning of school you set-up a 4 digit pin to get into your My Payments Plus account, however you have not used your account since you set it up and forgot the number. You remember that the first number was a 4 and the second number was either a 6, 7, 8, or 9. You had no idea what the last two numbers were. How many different combinations are possible?

Answer 1

Given that only the first digit and a range of four possible numbers for the second digit of the four digit pin number are remembered, the number of different possible combinations are 400 (possible combinations)

Explanation:

The given information are;

The number of digits contained in the pin = 4 digits

The number of digits that can be the first number = 1 (given that the first digit is 4)

The number of digits that can be the second number = 4 (6, 7, 8, or 9)

Therefore, we have;

The number of digits that can be the third number = 10 (0, 1, 2, 3, 4, 5, 6, 7, 8, or 9)

Similarly, the number of digits that can be the fourth number = 10

Therefore, the total number of possible combinations are;

1 × 4 × 10 × 10 = 400 possible combinations.