Frank has a box of pens. The box contains 6 blue pens, 8 black pens and 3 red pens. Some more blue pens are added to the box. The probability of selecting a blue pen is now 1/2. How many blue pens were added to the box?

The means and mean absolute deviations of the individual times of members on two 4x400-meter relay track teams are shown in the table below. means and mean absolute deviations of individual times of members of 4x400-meter relay track teams team a team b mean 59.32 s 59.1 s mean absolute deviation 1.5 s 245 what percent of team b's mean absolute deviation is the difference in the means? 9% 15% 25% 65%