Question

A bag contains 40 marbles, 4 of which are blue, 10 are red, 25 are green, and 1 is purple. Shawna takes a marble out of the bag, records the color, and returns it to the bag. How many green marbles should she expect after 400 trials?

A: 25
B: 40
C: 100
D: 250

Answer 1

The number of green marbles should expect after 400 trials = 250

Answer 2

Answer:

she expects 250 green marbles.

Explanation:

• note: there are total 40 marbles among which 25 are green
• as she puts it back, the total number will not change.
• probability = selected numbers/ total numbers
• repeats the experiment 400 times.

probability of getting green marbles after 400 trials:

→ ( $\frac{25}{40}$ ) * 400

→ 25 * 10

→ 250