We just started learning about this subject and I'm a little confused can you give me the answer to the problems and give an explanation on how to do it? or an easier way to do it.

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

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

80 points suppose marcy made 45 posts online. if 23 of them contained an image, what percent of her posts had images? round your answer to the nearest whole percent. 54 percent 51 percent 49 percent 48 percent