Question

Alan has forgotten his 4-digit PIN code.

He knows the first digit is 9 and the last digit is larger than 5.
How many different sets of 4 digits could it be?

Answer 1

• 400 sets

Explanation:

• First digit- 1 option (9)
• Second digit - 10 options (0 to 9)
• Third digit - 10 options (9 to 9)
• Fourth digit - 4 options (6, 7, 8, 9)

Possible number of sets:

• 1*10*10*4 = 400