Answer: Our required probability would be 0.35.
Step-by-step explanation:
Since we have given that
Number of boxes = 2
Number of purple marbles in Box A = 30
Number of yellow marbles in Box A = 20
Number of purple marbles in Box B = 15
Number of yellow marbles in Box B = 35
So, If Melanie randomly selects one of the boxes and then randomly selects one marble from that box.
Probability that the marble selected will be purple is given by
[tex]\dfrac{1}{2}\times \dfrac{20}{50}+\dfrac{1}{2}\times \dfrac{15}{50}\\\\=\dfrac{1}{2}(\dfrac{20+15}{50})\\\\=\dfrac{1}{2}\times \dfrac{35}{50}\\\\=\dfrac{35}{100}\\\\=0.35[/tex]
Hence, our required probability would be 0.35.