Math problem, how to re-scale

Hi,

I need a formula to convert a Speed input in a certain range to a time output range, problem is that the time is from high to low value...

My math is far away in my head, can anyone help in a simple method how I can find the right formula ? Thanks

Speed Input: 3 m/min - - - 20 m/min
Time output: 50s - - - 5s

Inverse the speed input in your programming?

20m/min beeing 0 and 3m/min being your max, let this correspond to the time. Where 0 is 5s and 50s is max.

if you use siemens s7 series you have scale (or scaleX and normX) functions that do that

As rQx mentioned, you will need to calculate the inverse of the speed ( .333 min/meter up to .05 min/meter) and then scale using that answer.

t=850/(9s-10)