For a hot air balloon to take off, the temperature of the air outside the balloon must be at least 20°F cooler than the temperature of the air inside of the balloon. In interval form, what is the temperature
inside the balloon if it is 53°F outside?

Abike shop sells you a bicycle for $63 and a helmet for $21. the total cost is 150% of what the shop spent originally. how much did the shop spend originally? how much profit did the bike shop earn by selling the bicycle and helmet to you ?

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.