Prehistoric cave paintings were discovered in a cave in France. the paint contain 25% of the original Carbon-14. Use the exponential decay model for carbon-14, A=A0e^-0.000121t to estimate the age of the paintings

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220