Choose the word from the drop-down menu that completes each sentence.

a/an__star system is made of two stars.

a/an__star system is made of no more than a few thousand stars.

a/an__star system is made of more than a million stars.

Abus travels 280km south along a straight path with an average velocity of 88km/h to the south. the bus stops for 24 min, then it travels 210 km south with an average velocity of 75 km/h to the south. how long does the total trip last?