As Leo drives to Toronto, the distance he is from Toronto (in miles) is given by d(t) = 500 − 50t where t is the amount of time which has passed since he started driving there (in hours). a) How long does it take Leo to drive to Toronto? b) How many miles does Leo travel each hour on his drive?

In a certain bacteria culture the rate of increase in a number of bacteria is proportional to the number of present. a) If the number triples in 5 hr, how many will be present in 10 hr? b)When will the number present be 10 times the numbers initially present?

A 30-second commercial during Super Bowl XXXVII in 2003 cost advertisers 2.2 million. For the first Super Bowl in 1967, an advertiser could have purchased approximately 26.19 minutes of advertising time for the same amount of money. (a) Assuming that advertising cost is proportional to its length of time, find the cost of advertising, in dollars/second, during the 2003 Super Bowl. cost= dollars/second. (round to nearest cent and do not enter commas) (b) Assuming that advertising cost is proportional to its length of time, find the cost of advertising, in dollars/second, during the 1967 Super Bowl. cost = dollars/second. (round to nearest cent and do not enter commas) (c) How many times more expensive was Super Bowl advertising in 2003 than in 1967? times more expensive (round to nearest whole number)

It is estimated that within ? years, the local newspaper circulation will be ?(?) = 100?2 + 400? + 5000. a)Obtain an expression for the rates of change of circulation respect the time ?.b)Which is the rate of change of circulation respect to ? equal to 5 years? Willdecrease or increase the circulation in this moment?c) How is the change of circulation during the sixth year?