How do I Change Spawning Time

My game has enemies that spawn ever 'random(5,8)seconds', but every 10 seconds I want the spawning rate to reduce to 'random(4,7)seconds' for example. How would I go about doing this?

easy... add a variable (local or global), for example 'x'. every 10 secs add 1 to x.

insert x to the spawn event:

random(5-x,8-x) seconds.

Of course you need to limit the x, so it wont be subtracted forever.

How do i create the limitation?

you can use:

while x <5

add 1 to x

Thanks so much!