Answer: 11 goes in the blank in the denominator
The probability as a fraction is 5/11
============================================================
Step-by-step explanation:
There are 250 red and 300 blue. This gives 250+300 = 550 total marbles.
Divide the number of red (250) over the number total (550) to get the fraction 250/550. Reduce this fraction by dividing both parts by 50. Note how 50 is the GCF of 250 and 550.
Let A = 250 and B = 550.
- A/GCF = 250/GCF = 250/50 = 5 which is the numerator already written for us
- B/GCF = 550/50 = 11 will go in the blank in the denominator
The fraction A/B = 250/550 fully reduces to 5/11.
We can think of it like saying "There are 5 red marbles out of 11 total".
5/11 = 0.4545 = 45.45% approximately