Question

Ram forgot his bank account PIN which is a 5 digit number but luckily he remembered some hints
on how to recall this PIN.
Here are some of the clues.
(A) 1
st digit is a square of the 2nd
.
(B) Sum of 2nd and 3rd is 10.
(C) 4
th is equal to the 2nd plus 1.
(D) Sum of all digits is 30.

Answer 1

Finding the PIN

Solution:

• Let the PIN be A B C D E.
• We have to find the values of A, B, C, D, E, and determine the PIN.

Condition 1. The 1st digit is a square of the 2nd digit

• Then A = C²
• The possible values of A are 4, 9.

1. When A = 4, C = 2
2. When A = 9, C = 3

Condition 2. Sum of the2nd digit and the 3rd digit is 10

• Then B + C = 10

1. When C = 2, B = 8
2. When C = 3, B = 7

Condition 3. The 4th digit is equal to the 2nd digit plus 1

• Then D = B + 1

1. When B = 8, D = 9
2. When B = 7, D = 8

Condition 4. Sum of all the digits is 30

• Then A + B + C + D + E = 30

1. When A = 4, B = 8, C = 2, D = 9, E = 7
2. When A = 9, B = 7, C = 3, D = 8, E = 3

We have found two PINs:

1. 4 8 2 9 7
2. 9 7 3 8 3