Answer:
30 blue pins
Step-by-step explanation:
30% is the same as 30 out of 100, so this can be written in this fraction: 
now, you should multiply this fraction by the total number of pins she ordered:
100 x 
to solve this, you can simplify by dividing 100 by 100, this equals 1
30 times 1 is 30
there are 30 blue pins
If by description you mean simplification then: 84x/28
The fraction 8/21 cannot be simplified because the numerator and denominator don't have a common factor except 1.