Julie and Dale live in Gridtown. The streets running north/south are parallel with one another as are the streets running east/west. Every time that Julie and Dale walk, they record how far they have travelled. The distance between each block is 100 m. During their most recent walk around Gridtown, Julie and Dale left home and travelled 6 blocks north to the Fruit Market before turning right. Then they walked 4 blocks east to the Library . They turned right again and walked 3 blocks south to the Pet Store. Then they walked 2 more
blocks east to the park.

If they take the shortest route back home, how far will they have travelled in total?

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