Question Number 50450 by JDlix last updated on 16/Dec/18
$${how}\:{many}\:{trips}\:{can}\:{a}\:{bird}\:{moving}\:{in}\:\mathrm{120}{m}/{s}\:{make} \\ $$$${between}\:{two}\:{trains}\:{which}\:{are}\:{initially}\:\mathrm{120}{m}\:{apart}\:{and} \\ $$$${moving}\:{in}\:\mathrm{60}{m}/{s}\:{to}\:{each}\:{other}? \\ $$$$ \\ $$