Answer:
C. 5 Red marbles
Step-by-step explanation:
If she started with 5 red marbles and had a probability of 1/5 of drawing a red marble, then there were 20 blue marbles, and 25 total marbles.
5/25 = 1/5
If she added 5 red marbles, she now would have 10 red marbles and still 20 blue marbles, giving her 30 total marbles in the bag.
10/30 = 1/3, so C is the right answer.
You can rule out other choices by repeating the above steps and substituting appropriate values
Walmart: 10 pens/$8.99 -> $.89/pen
Walgreens: 25 pens/$19.75-> $.79
Walgreens has the better deal
El tenia $325
$250+$75=$325
Espero q te ayude :)
