₦airaland Forum

Brain exercise:
A housewife forgot her Bank account PIN Code which is a 5 digit number, but luckily she remembered some hints on how to recall this PIN Code.
Here are some of the clues:
1) The first digit is the square of the 2nd.
2) The sum of the 2nd and 3rd is 10.
3) The 4th is equal to the 2nd plus 1.
4) The 3rd and 5th makes just 14.
5) The sum of all the digits is 30.
What's the PIN Code?

lalasticlala

Let the first digit be v
the second w
the third x
the forth y
the fifth z
~
v = w^2
w+x =10
y = w+1
x +z = 14
v+w+x+y+z=30
express all eqn in terms of w
therefore:
v=w^2
x=10-w
y=w+1
z=14-(10-w)
z=4+w and;
w^2 + w + (10-w) + (4+w) = 30...open brackets
w^2 +2w + 15 = 30
w^2 + 2w - 15 = 0...using the almighty formula:
w=3 or -5...ignoring the negative value, subs w=3 in the each eqn to get v,x,y and z
v=3^2=9
x=10-3=7
y=3+1=4
z=4+3=7
9+3+7+4+7=30
the pin is 93747



ImperfectMe:
Let the first digit be v
the second w
the third x
the forth y
the fifth z
~
v = w^2
w+x =10
y = w+1
x +z = 14
v+w+x+y+z=30
express all eqn in terms of w
therefore:
v=w^2
x=10-w
y=w+1
z=14-(10-w)
z=4+w and;
w^2 + w + (10-w) + (4+w) = 30...open brackets
w^2 +2w + 15 = 30
w^2 + 2w - 15 = 0...using the almighty formula:
w=3 or -5...ignoring the negative value, subs w=3 in the each eqn to get v,x,y and z
v=3^2=9
x=10-3=7
y=3+1=4
z=4+3=7
9+3+7+4+7=30
the pin is 93747



Waohh. That's all I can say