Bank Math Master১টি পরীক্ষায় এসেছেপ্রশ্ন ২০A man covers half of his journey at 12 km/h and the remaining half at 6 km/h. His average speed is-ক10 km/hখ8 km/hগ7 km/hঘ9 km/hউত্তর দেখুন