In 6 hours a boat, traveling with the current, covers 20 more mi than in 10 hours, traveling against the current. what is the speed of the current if the speed of the boat in still water is 15 mph?

The rate of decay of a radioactive substance depends upon the amount present initially. the mass y (mg) of the radioactive substance cobalt-60 present in a sample at time t (years) is represented by the exponential equation y=50e −0.1315 t . answer the following questions in complete sentences. 1. how does the exponential equation above compare to the equation for simple interest that is compounded continuously? explain the similarities. 2. what is the initial amount of cobalt-60 in the sample? 2. how much cobalt-60 is left after 8.4 years? show your work. 3. what would be the y-intercept of the graph? what does it represent? 4. after how many years will the amount of cobalt-60 left be 6.25 mg? explain what happens to the cobalt-60 after 50 years? 5. discuss some “real-world” examples and uses of cobalt-60

14. (05.02 lc) what is the value of y in the solution to the following system of equations? (5 points) 2x + y = −4 5x + 3y = −6

Which inequality is equivalent to -3x < -12? x < 4 , x < -4 , x > 4, x > -4