Question

The 4-digit PIN for one of my credit cards consists of four different digits. The sum of the first two digits is 12 and the sum of the last two digits is 15.

Which one of the following additional pieces of information is sufficient by itself to enable deduction that the PIN is 7569?

A. Second digit × third digit = 30
B. Fourth digit – first digit = 2
C. Third digit – second digit = 1
D. First digit × fourth digit = 63

Answer 1

Answer:

D or A

Explanation:

I think the additional piece of information that is most sufficient is D because the only numbers that are single digits and make 63 are 7 and 9. So we know the first digit is 7 and the next digit must be 5 to sum up to 12 and for 9, the third digit must be 6.

But, it could also be A, the only numbers that are single digits of that have the product of 30 are 5 and 6. Likewise 7 being the first digit to make 12 and 9 being the last to sum up to 15.

Hope this helps, but of course this is my opinion so I might be wrong or right.