18 The table gives information about the times, in hours, some students spent doing sport one week.
Time (T hours)
Frequency
0 5
2 <134
9
4 24
6 40
8 7
Calculate an estimate for the mean time these students spent doing sport.
Give your answer in hours, correct to 1 decimal place.
help pls

Which of those sequences is a geometric sequence

Bring the fraction a/a-4 to a denominator of 16-a^2

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered