Diego has 7 packs of markers. each pack has x markers in it. after lin gives him 9 more markers, he has a total of 30 markers

For this case we must find:
 x = the number of marbles in a package.
 For this, according to the statement we have the following equation:
 7x + 9 = 30
 Clearing x we have:
 7x = 30-9
 x = 21/7
 x = 3 marbles
 
 Each pack of marbles contains 3 marbles

29. because you will divide each number of months by 12 to find the number of years. which would mean, 5, 12.5, 16, 45, 50, 72.5. which is crazy. anyhow, i think you find the median in the middle. and yea hope your test goes good