NUN Shadib operates a printing machine and the cost, in dollars, of operating this machine per day
is given by the formula C = 2r? - 841+ 1025 where t is the time, in hours, the machine
operates
a) What is the minimum cost of running the machine and for how many hours must the machine
run to reach the minimum cost?
b) On a certain day the cost of running the machine was estimated to be close to $300. For how
many hours could the machine have been operating on that particular day? Fully explain your
answer

At wind speeds above 1000 centimeters per second (cm/sec), significant sand-moving events begin to occur. wind speeds below 1000 cm/sec deposit sand and wind speeds above 1000 cm/sec move sand to new locations. the cyclic nature of wind and moving sand determines the shape and location of large dunes. at a test site, the prevailing direction of the wind did not change noticeably. however, the velocity did change. fifty-nine wind speed readings gave an average velocity of x = 1075 cm/sec. based on long-term experience, σ can be assumed to be 245 cm/sec. (a) find a 95% confidence interval for the population mean wind speed at this site. (round your answers to the nearest whole number.) lower limit cm/sec upper limit cm/sec