The following nine values represent race finish times in hours for a randomly selected group of participants in an extreme 10 km race (a 10 km race with obstacles). Which of the following is closest to the mean of the data set? 1.0,1.1,1.2,1.2,1.3,1.4,1.4,1.4,1.5
a) 1.1 hours.
b) 1.5 hours.
c) 1.3 hours.
d) 1.6 hours.

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

Three coins are flipped. what is the probability that there will be at least two tails?

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?