There are 72 green pens.
There is 9 times as many white pens from 2 to 18, so there has to be 9 times as many green pens because of the ratio. 9 times 8 is 72.
Must be 16 and 21 because we can see
30 and 70 has 10 as factor
24 and 44 has 2 as factor
12 and 30 has 2 as factor and all those factors are greater than one
2³ + 3² = 2*2*2+3*3= 8+9=17
a=2,
b=3,
P= 17,
2,3,17 are all prime numbers