A safety inspector determines that contamination from an abandoned factory site is spreading through the surrounding soil towards a nearby playground at the rate of 8 inches per year. At that rate, how many years will it take for the oil to spread 20 feet towards the playground? (12 inches = 1 foot)

A toxic radioactive substance with a density of 9 milligrams per square cm is detected in the ventilating ducts of a nuclear processing plant that was used 55 years ago. If the half life is 20 years, what was the density of the substance when it was depoited 55 years ago?

A    26    foot    ladder    is    sliding    down    a    vertical    wall.        The    base    of    the    ladder    is    sliding    away    from    the    wall    at    a    rate    of    3    feet    per    minute. If    you    consider    the    triangle    formed    by    the    ladder,    the    wall,    and    the    ground,    at    what    rate    is    the    area    of    the    triangle    changing    when    the    base    of    the    ladder    is    10    feet    from    the    wall?What    does    the    sign    of    your    answer    (whether    it    is    positive    or    negative)    say    about    the    area    of    the   triangle    at    that    moment?Would    you    expect    the    rate    at    which    the    area    is    changing    to    have    the    same    sign    (positive  or negative)    when    the    base    of    the    ladder    is    any distance    from    the    wall?

A student is concerned with the amount of air pollution students are exposed to in the school's parking lot after school. The student conducts an investigation to compare the quantity of particulate matter released from the diesel-powered buses, natural gas-powered buses, and the large and small cars as they idle waiting to pick up students. To make measurements, a small piece of white fabric is used to collect particulate matter from the tailpipe of each vehicle as it idles for five minutes. Each piece of fabric is then analyzed to measure the amount of particulate matter it collected. (i) Identify the independent variable in the investigation. (j) Identify one variable that was not mentioned in the description that could affect the results of the investigation. (k) Describe a realistic alternate sampling method to collect particulate matter from the vehicles in the investigation. (1) The student wants to ensure that the results are reliable. Explain how the student could modify the…