Explain what is 21=m + 14 1/6

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

The areas of two similar triangles are 72dm2 and 50dm2. the sum of their perimeters is 226dm. what is the perimeter of each of these triangles?

The evening newspaper is delivered at a random time between 5: 30 and 6: 30 pm. dinner is at a random time between 6: 00 and 7: 00 pm. each spinner is spun 30 times and the newspaper arrived 19 times before dinner. determine the experimental probability of the newspaper arriving before dinner.