you can take an oszillator with 2500Hz as master clock. Then you take a two decade counters like SN74LS90 and connect them as shown in the attached circuit.
You can see, that the first counter is connected in differentway as the second. The first counter get his clock at input "B". So you get at output pin 11 a signal divide by 5 with 500 Hz. This output is connect to the input "A". The signal at output pin 12 is divide by 2. Now this output is connect to the second counter. This counter divides the input signal by 10, so that you get 25Hz at the output pin 11.
All clocksignals are dependent from the master clock.