[Guest]

Each of A, B, C and D is a positive integer with the proviso that A <= B <= C <= D <= 20

Determine the total number of quadruplets (A, B, C, D) such that A*B*C*D is divisible by 100.

Edited April 1, 2010 by K Sengupta

[Guest]

2352 ways. I hope i didnt miss anything or double count anything

Edited April 1, 2010 by DeeGee

[Guest]

I got a different answer than DeeGee

I got 1358.

Sub findabcd()

num = 1

For a = 1 To 20

For b = a To 20

For c = b To 20

For d = c To 20

prod = a * b * c * d

If (prod Mod 100 = 0) Then

Cells(num + 1, 1) = num

Cells(num + 1, 2) = a

Cells(num + 1, 3) = b

Cells(num + 1, 4) = c

Cells(num + 1, 5) = d

Cells(num + 1, 6) = prod

num = num + 1

End If

Next

Next

Next

Next

End Sub

[superprismatic]

I agree with BebopKid.

Edited April 1, 2010 by superprismatic