Cecelia studied for the sat for 20 minutes every day in the first week, 30 minutes in the second week, 40 minutes in the third week, and 50 minutes in the fourth week.
christopher studied for the sat for 5 minutes every day in the first week, 10 minutes in the second week, 20 minutes in the third week, and 40 minutes in the fourth week.
which statement best describes the methods used by cecelia and christopher to increase the time they spent studying?
a. cecelia's method is exponential because the number of minutes increased by an equal number every week.
b. christopher's method is exponential because the number of minutes increased by an equal factor every week.
c. both christopher's and cecelia's methods are linear because the number of minutes increased by an equal factor every week.
d. both christopher's and cecelia's methods are linear because the number of minutes increased by an equal number every week.

What is the length of the segment joining the points at (4,5) and (6,-2) round to the nearest tenth if necessary

If my mom gets $13.05 an hour, and she works from 3: 30 to 10: 45 in the morning, how much money does my mom make?

Aprisoner is trapped in a cell containing three doors. the first door leads to a tunnel that returns him to his cell after two days of travel. the second leads to a tunnel that returns him to his cell after three days of travel. the third door leads immediately to freedom. (a) assuming that the prisoner will always select doors 1, 2 and 3 with probabili- ties 0.5,0.3,0.2 (respectively), what is the expected number of days until he reaches freedom? (b) assuming that the prisoner is always equally likely to choose among those doors that he has not used, what is the expected number of days until he reaches freedom? (in this version, if the prisoner initially tries door 1, for example, then when he returns to the cell, he will now select only from doors 2 and 3.) (c) for parts (a) and (b), find the variance of the number of days until the prisoner reaches freedom. hint for part (b): define ni to be the number of additional days the prisoner spends after initially choosing door i and returning to his cell.