A fireman is on the middle step of a ladder. (There are the same number of steps above him as below him.) If he goes down 4 steps, then up 7 steps, and then down 13 steps, he will be on the first step above the ground. How many steps does the ladder have?

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days