Take a look at code after small changes:
Dim days As Variant, percent As Variant, sTmp As String
Dim wsh As Worksheet
Set wsh = ThisWokbook.Worksheets("Sheet1")
days = Array("015", "1530", "3160", "6190", "g90")
percent = Array("7080", "8090", "g90")
For i = LBound(days) To UBound(days)
For j = LBound(percent) To UBound(percent)
sTmp = "cnt" & percent(j) & "_" & days(i)
wsh.Cells(rowc, k).Value = sTmp
rowc = rowc + 1
Next
k = k + 1
rowc = 7
Next
Set wsh = Nothing
I'd strongly recommend to read this:
Coding Techniques and Programming Practices[
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