Plz, help me with all of these

Which rational number could be graphed between -4 and -5

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

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?