A scientist measures the initial amount of carbon -14 in a substance to be 25 G the relationship between a and the amount of carbon -14 remaining in that substance in grams and t the elapsed time in years since the initial measurement is modeled in the following equation A= 25e^0.00012t how many years will the substance contain exactly 20 grams of carbon -14 give an exact answer expressed as a natural logarithm

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. a new supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which size bag provides the best deal, and how much will you save each month? compare the cost of the new supplier to the current one.