A brother and sister are comparing their ages. The older sister is 8 years less than twice the brother’s age. The sum of their ages is 25 years. Let "x" be the age of the brother. Set up and solve an equation for x.

You decide instead to take the train there. the train will take 135 minutes. convert this into hours and minutes.

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

Ron has 8 caps and 4 of his caps are blue. thes rest of his cap are red. how many of ron's caps are red