15)
apples: 30%
-> oranges:100-30=70%
25% are ripe apples, 50% are ripe in total-> 50-25=25% are ripe oranges
oranges-ripe oranges=not ripe oranges
70-25=45% not ripe oranges=B
16)
the first relevant number is 12, the largest 27
the 6 numbers 12,15,18,21,24,27 are divisible by 3
subtract 2, because 18 and 27 is divisible by 9
6-2=4=E
