The ATM pin is 3635
Step-by-step explanation:
Let the first digit be 'a'
Second digit be 'b'
Third digit be 'c'
Fourth digit be 'd'
Some hints are given,
a = b/2
b + c = 9
d = b - 1
a + b + c + d = 17
a + b + c + d = 17
a + 9 + d = 17
a + d = 8
d = b-1
a = b/2
b + c = 9
So,
a + b + c + d = 17
b/2 + 9 + b-1 = 17
b/2 + b + 8 = 17
3b/2 = 9
3b = 18
b = 6
a = b/2
a = 6/2
a = 3
b + c = 9
6+c = 9
c = 3
d = b - 1
d = 6-1
d = 5
So,
a = 3
b = 6
c = 3
d = 5
So the ATM pin is 3635