The half-life of radium-226 is 1590 years. (a) a sample of radium-226 has a mass of 200 mg. find a formula for the mass of the sample that remains after t years. (b) find the mass after 1000 years correct to the nearest milligram. (c) when will the mass be reduced to 30 mg?

It took alice 5 5/6 hours to drive to her grandparents' house for . on the way home, she ran into traffic and it took her 7 3/8 hours. how much longer did the return trip take? write your answer as a proper fraction or mixed number in simplest form. the trip home took __hours longer. ?

Alogical argument that is presented in graphical form using boxes and arrows is called?

Find the area of the triangle formed by the origin and the points of intersection of parabolas y=−3x^2+20 and y=x^2−16.