which of these is true about the total amount of energy in a closed system?

decreases
destroyed and created
increases
remains the same

17 a tourist was planning a trip by car for travelling at some constant speed for 2.5 hours. however, he found that if he increases the speed by 20 km/h he can cover the same distance in 30 minutes less time than it was planned. what was the planned speed of the tourist, in km/h?

You can reduce glare in snowy weatuer by?

Abox contains 40 number tiles numbered 1 to 40. if a tile is drawn at random, what is the probability that the number drawn is a multiple of 3 or 4? find p(multiple of 4 or multiple of 5)