A sample of a radioactive isotope had an initial mass of 610 mg in the year 1990 and decays exponentially over time. A measurement in the year 1992 found that the sample's mass had decayed to 340 mg. What would be the expected mass of the sample in the year 1997, to the nearest whole number?

If sr is 4.5cm and tr is 3cm, what is the measure in degrees of angle s?

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?