The rate of decay in the mass, M, of a radioactive substance is given by the differential equation dM dt equals negative 1 times k times M, where k is a positive constant. If the initial mass was 150g, then find the expression for the mass, M, at any time t. M = e−kt
M = 150 ekt
M = 150 e−kt
M = 150ln(kt)

1. what is the formula for finding the vertical distance between two points on a coordinate plane?

The cost of turkey is directly proportional to its weight. if a 12-pount turkey costs $27, how much does a 16-pound turkey cost? a. $33.75 b. $36.00 c. $31.00 d. $32.50

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.