Element X is a radioactive isotope such that every 81 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 1800 grams , how much of the element would remain after 28 years , to the nearest whole number?

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 23 = 10x a. -1.93, 11.93 b. 1.93, -11.93 c. 1.93, 11.93 d. -1.93, -11.93

The cost of a taxi ride includes an initial charge of $2.00. if a 5km ride cost $6.00 and a 10km ride cost $10.00, determine the cost of a 15km ride.

1. why is a frequency distribution useful? it allows researchers to see the "shape" of the data. it tells researchers how often the mean occurs in a set of data. it can visually identify the mean. it ignores outliers. 2. the is defined by its mean and standard deviation alone. normal distribution frequency distribution median distribution marginal distribution 3. approximately % of the data in a given sample falls within three standard deviations of the mean if it is normally distributed. 95 68 34 99 4. a data set is said to be if the mean of the data is greater than the median of the data. normally distributed frequency distributed right-skewed left-skewed