VBA if condition is true, however actually is false, what's wrong with it?

Question

I wrote code in VBA to extract data from Access database to Excel based on some input parameters. When it comes to If statement, one of the criteria which exam the range of "Speed" variable is true, however, I checked that this criteria should be wrong. For example, speed=49, VSP=1.5, 1<=Speed<25 in 1st if condition indicates true which is ridiculous, and VSP<0 indicates false, so it goes to 1st elseif condition, 1<=Speed<25 still indicates true and 0<= VSP<3 is also true, then function returns the value from Access database. Else, if speed=49, VSP=6.5, the function still executes the "ElseIf (1 <= Speed < 25) And (0 <= VSP < 3) Then, statement 2" part. It seems it only always regard 1st elseif condition as true.

What's wrong with my if statement? Any advice?

Code:

Function F (ByVal Speed, VSP as single)

.............

If (1 <= Speed < 25) And (VSP < 0) Then

   statement 1

ElseIf (1 <= Speed < 25) And (0 <= VSP < 3) Then

   statement 2

ElseIf (25<= Speed < 50)) And (0<= VSP <3) Then

   statement 3

End if

End function

Answer 1

Nobody has yet pointed how 1 <= Speed < 25 is evaluated. First, 1 <= Speed is evaluated as True or False, then that value is compared with 25. This requires interpreting True or False as an integer. True is interpreted as -1; False is interpreted as 0. Both of these are less than 25, so the expression will always evaluate to True.