Respuesta :
Answer: [tex]\bold{\dfrac{1}{35}}[/tex]
Step-by-step explanation:
[tex]\dfrac{\# \text{of blue marbles}}{\text{total marbles}}\times \dfrac{\#\text{of yellow marbles}}{\text{total remaining marbles}}\\\\\\=\dfrac{6}{21}\times \dfrac{2}{20}\\\\\\=\large\boxed{\dfrac{1}{35}}[/tex]