Let me provide some facts about a couple of integers m and n:
- One of them is a 3-digit number, the other is a 2-digit number
- One of them is divisible by 11
- One has all its digits distinct
- The last digit of m^3 equals the last digit of n
- The last digit of n^3 equals the last digit of m
a. Evaluate the maximum value of m+n.
b. What possible values can m*n reach?
(In reply to
part b in more concise form by Charlie)
DefDbl A-Z
Dim crlf$
Private Sub Form_Load()
Form1.Visible = True
Text1.Text = ""
crlf = Chr$(13) + Chr$(10)
For a = 100 To 999
For b = 10 To 99
If a Mod 11 = 0 Or b Mod 11 = 0 Then
astr$ = LTrim(Str(a)): bstr$ = LTrim(Str(b))
good = 0
If Mid(astr, 1, 1) <> Mid(astr, 2, 1) And Mid(astr, 1, 1) <> Mid(astr, 3, 1) And Mid(astr, 3, 1) <> Mid(astr, 2, 1) Then good = 1
If Mid(bstr, 1, 1) <> Mid(bstr, 2, 1) Then good = 1
If good Then
a3 = a * a * a: b3 = b * b * b
If a3 Mod 10 = b Mod 10 And a Mod 10 = b3 Mod 10 Then
Text1.Text = Text1.Text & a & Str(b) & " "
Text1.Text = Text1.Text & mform(a + b, "###0") & mform(a * b, "#####0") & " "
Text1.Text = Text1.Text & mform(a3, "##########0") & mform(b3, "######0") & crlf
If a + b > maxsum Then maxsum = a + b: mxsa = a: mxsb = b
If a * b > maxprod Then maxprod = a * b: mxpa = a: mxpb = b
End If
End If
End If
DoEvents
Next
Next
Text1.Text = Text1.Text & maxsum & Str(mxsa) & Str(mxsb) & crlf
Text1.Text = Text1.Text & maxprod & Str(mxpa) & Str(mxpb) & crlf
Text1.Text = Text1.Text & crlf & " done"
End Sub
Function mform$(x, t$)
a$ = Format$(x, t$)
If Len(a$) < Len(t$) Then a$ = Space$(Len(t$) - Len(a$)) & a$
mform$ = a$
End Function
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Posted by Charlie
on 2016-11-16 10:22:00 |
the program
