3(4+n)=18+n
distribute
12+3n=18+n
minus n both sides
12+2n=18
minus 12 both sides
2n=6
divide by 2
n=3
the number is 3
equation is
3(4+n)=18+n
7.5 .. multiply .05 times 150
The numbers that are divisible by 3 are:
3, 6, 9, 12, 15, 18, 21, 24
that is 8 numbers divisible by 3
24-8=16 numbers NOT divisible by 3
so the probability of not picking a number divisible by 3 is 16/24
hope this helps and is right :)