For a constant collector-emitter voltage of \( 8 \, \text{V} \), the collector current of a transistor reached to the value of \( 6 \, \text{mA} \) from \( 4 \, \text{mA} \), whereas base current changed from \( 20 \, \mu\text{A} \) to \( 25 \, \mu\text{A} \) value. If transistor is in active state, small signal current gain (current amplification factor) will be: