It seems like there might be some missing or unclear information in your question. To calculate their speeds, we need both the distance they biked and the time it took.
Mia biked 1.25 km, but there is no provided time frame for her. Jamal biked 1.75 km in 7 minutes, but it's unclear what you mean by "in 4 minutes."
Could you please provide the complete and clear information about the distances they biked and the time it took for each of them?