Mr. Avogadro started with 5.14x10^22 atoms of Pa-234. Ten days later Mr. Avogadro calculated the original sample had only 6.43 X 10^21 atoms of Pa-234. What's the half life of Pa-234? PLEASE HELP WILL MARK BRAINLIEST

What aspects of lines have to be diffrent

Which image (a’ b’ c’ d’) of abcd cannot he produced using only reflections ?

More than 450450 students traveled to a state park for a field trip. the school allowed 66 students to travel by car, and the rest traveled on 1111 buses, each of which held the same number of students. if there were ss students in each bus, which inequality best represents this situation?